I actually have a pair of gray suede peep toes, and I wear them after the snow has melted until about the end of april, maybe the first week or so of May. Usually by Mother's Day I've put them away until fall.
Depends on the climate where you live. If it's still chilly, I say it perfectly fine to wear suede until it gets too warm to do so. If it's 80 degrees in April, suede would be the last thing I'd want to walk around in.
I, too, wear suede year-round. I have a lovely pair of teal t-straps that are fantastic with summer dresses. And a pair of olive peep-toes that look good with lightweight skirts. I think a lot of it has to do with the style of shoe, too.
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