i do it but dd is only 16 months so it could still fail miserably. maybe i have more time on my hands with just one and SAH but i scour a nearby salvation army every so often where apparently enough well-to-do folks drop off their name brand kids clothes. so in that case i always buy. especially coats, i think i have up to 4t and they tend to run pretty generous (dd is still wearing a hand-me-down 9 mo size which her 2 yo cousin also fits in....huh....) so i figure there's gotta be one that'll fit for any year.
i also like the sale racks at target. every so often the cutest stuff is marked down to like $1.75 and around there. in any case, since i'm buying ahead and dd has plenty, i don;t buy anything over $5.00 unless it's extraordinary.
it also might be easier to make this work with a girl because you can fudge on sizes so much just due to the type of clothes. she's been wearing 2T peasant tops as dresses since she was an infant and they just stay in her closet until they fit her more like a shirt. or vice versa she can wear a too-small dress as a top. seriously there's a 3-6 month sweater in her closet that she still wears.
and i don't worry so much about seasons. i can always layer in the winter so at some point everything's gonna get use..i think.
there are a couple items i took gambles on like a summer romper type thing which pretty much can only be worn when it's hot and has to fit but since i bought it for like $3 it's water under the bridge if it doesn't work out. there may be another kid down the line, either mine or a friend's, who can wear it. (or you could consign!)