Smash would be great to help with this topic...I remember her posting several times on FH about it.
I think it depends on your style. My staples are black flats, white button-down, grey trousers, great-fitting jeans and lots of cardigans and tanks in bright colors.
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"We live in an age where unnecessary things are our only necessities." --Oscar Wilde
i personally define basics as the things worn the most often. i think everyone should have at least 5 pieces of clothing that work with practically everything else in their closet. for some people this is the old standby of white blouse, black pants, black sweater, etc. that way, you can never really say "i have nothing to wear" because there is always a component that you can build an outfit around.
for me, it's a fitted black 3/4 sleeved tee, a camel faux suede a-line knee-length skirt, a vintage light wash denim blazer, grey trousers, and a soft kelly green cashmere sweater. i can make outfits using these pieces together or i can break them up and wear them with pretty much everything else that i own. they all fit me perfectly and make me feel comfortable and good about myself. if i could pick only 5 things to wear for the rest of my life (assuming accessories and underwear were also included - heh), i would easily say those pieces.
for the longest time i thought that “basics” were these specific items that everyone HAD to have to be able to dress themselves every day, but then i realized that this is a concept created by the fashion and magazine industry (more magazine than fashion) to attempt to simplify our closets and quell our paranoia about whether we have the "right" thing to wear. so while some of the well-known basics are things that i own, like white tee, white button-down, dark jeans, black slingbacks, etc, there are lots of things on the lists out there that just don't work for me personally. like a trench coat. i would never wear one (i'm more of a retro jacket kinda gal and i can't live without my orange windbreaker and denim blazer), so it isn't essential or practical for me to own one. i also don't like the way black pants or skirts look with any tops (again, my personal preference), so i don't own any of those either. but those are two “basics” for other gals out there.
so i don't believe that there are certain things that *everyone* should have in their closet. but i do think everyone should have their 5 "can't live without" pieces.
if you are really looking to revamp your whole closet and you want good guidance, i recommend buying that Lucky shopping book – it is a good overview of what basics are important and how to figure out which versions of the basics will work best for your style and wardrobe. it also talks about how things should fit and be taken care of. it's a really good thing to have. so i would recommend picking it up for guidance in your quest to rebuild your closet.
honey is actually really good at posting specific items that people should have in their closets. i think i saved a post that she made on FH about this - i'll look and see if i still have it.
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"to be nobody but yourself in a world which is doing its night and day to make you everybody else, means to fight the hardest battle which any human being can fight, and never stop trying." - ee cummings
ok, i found the FH post that honey had made a while back about basics, so i figured i would post it here. hopefully she doesn't mind!
*dress pants -- look for a neutral color, the most obvious is black, but gray, brown, and camel are also great neutral colors. the key is to find a pair that fits you perfectly. you should put them on and feel kick ass. if you have any doubts about them you definitely shouldn't buy them b/c it's better to have 1 amazing pair of pants, then 20 so-so pairs (and i speak from personal experience). length is also really important. imo the hem should hit right before the ground (not drag on the ground, but not high waters either). also you can look into getting a pair to wear w/ flats and a pair to wear w/ heels.
*casual pants -- same idea as before but in less formal fabric (i.e. corduroy) or an interesting pattern/texture etc.
*dress skirt -- i think a lines tend to be the most universally flattering, but i also really like pencil skirts. again pick a neutral color and opt for something on the longer side (i.e. no minis) i like skirts that end right below the knee, but that's my preference. (for some reason i don't really like skirts that hit at the knee, but i'm strange) also if you have thicker calves you should probably look for a length that's slightly above the knee or at the knee, since if you go too low (i.e. mid-calf) it will just make your calves look bigger. ideally you could get one a-line skirt and one pencil skirt.
*casual skirt -- same rules as above, but you can go with a mini (not a micro) if you're comfy with that. i vote for denim. the most versatile pieces in my wardrobe are my dark denim skirts (i have a pencil skirt, a tulip skirt, a-line, the list goes on). admittedly i'm a big skirt person. but dark denim is an amazing neutral color (it looks good with everything), and a dark denim skirt is a good way to be casual, but still polished.
*jeans -- invest in a good pair, but remember that "invest" doesn't mean buy the most expensive. again, dark denim is the way to go. it's really worth it to just take a day and go from store to store and just try on jeans and find a pair that works for your body. imo, there's not one brand of universally flattering jeans, so try them all. if you can swing it get a pair that's more dressy (longer length (for heels), darker denim to wear at night) and a casual pair, ideally to wear with sneakers.
*button down -- this is kind of tricky b/c it again depends on your style. some people will automatically say white button, but only get one if they work with your style. definitely get something with stretch. it will hold it's shape better, and flatter your figure. if you go with a button down, i would recommend something with an elbow or 3/4 length sleeve (can wear year round) and i really like black for button downs. i have a black one that i wear way more than my white
*tees -- again i'm not a big fan of the basic tee. it's a little bland. though i do like the c & c style tees b/c the cuts and ability to layer make them more interesting. which means you can in theory wear a tee & jeans, and not look like you're wearing a "tee & jeans" old navy makes a nice c & c knock-off (wide neck, sheer) that's only ten bucks. again it's a matter of preference.
*a nice dress -- not too short. if you're only going to buy one go with black or another solid color, this way you can add accessories for new looks. if you're only buying don't get a spaghetti sleeve or strapless (imo you should have more than one, but we're talking basics) sleeveless is fine, but something that will cover bra straps. elbow length and cap (depending on your body) also work well and can be worn to work, or a more formal occasion when paired with the right accessories.
*jackets -- one casual (short length, light fabric) one formal (longer, more substantial material). imo, nothing makes you look more pulled together than a nice coat, not necessarily expensive. a good coat can really make you look polished, even if the rest of your outfit is meh.
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"to be nobody but yourself in a world which is doing its night and day to make you everybody else, means to fight the hardest battle which any human being can fight, and never stop trying." - ee cummings
I'll second what smash has said about finding your own basics and essentials. I think it's really about thinking about your lifestyle (job, leisure time, ect) and what kind of clothes you need for that. For me, the 'basic' wardrobe pieces that magazines tout as a must-have for every woman from here to Australia simply wouldn't work at all for me. White t's bore me (I don't own a single plain white t, or black for that matter), I hate button down shirts, khakis don't really thrill me either, I would get no use out of suits, and yet these things are ubiquitous on magazines' It Lists.
That said, there are some things that I find work well for me and my lifestyle and I find myself coming back to again and again. Denim is essential and my closet has many incarnations of this fabric. My job allows me to wear denim whenever I feel like it. My denim basics include, a denim skirt that hits just above the knee, dark denim jeans, light denim jeans, a light wash denim blazer and a dark wash denim blazer. I also love simple camisoles (stretchy and seamless). They go under anything and are great for layering. I have about 20 in all different colors. A few nice pairs of pants (mine are Editors, for the most part) in various colors (black pinstripe, grey, brown). I also have several different kinds of cardigans. I've found that with these pieces I can create several different outfits with other things in my closet.
Again, it's all about your lifestyle and what suits you.