I used to never buy in advance of the season, because I chased sales - or maybe I should say
that I bought so late in the season that I was buying in advance of the
next year's season! In recent years I've found that some judicious buying ahead of the season works much better for me - I can wear things right away once the weather changes, rather than have to go shopping for something essential. I think that if you have a classic style, you can get away with buying out of season more easily than if you prefer being trend-driven, because things may change by the time the season comes back around.
Just one example: last winter I found a pair of black sandals at NR -
Ecco, so a good quality brand, and at least half off full price. I knew
that I needed to replace my nice black sandals by summer, so I went
ahead and bought them. I didn't wear them for four or five months but
I've been wearing them happily all summer. I guess I could have bought
something with that money that I could have been wearing sooner, but
then I might have had to spend more money on something similar when
summer came, or not been able to find something that worked for me.
I've definitely had regrets for not snapping things up that sell out in my size or go up significantly in price afterwards. It's true that sometimes they get better in your mind once you've missed out on them - the grass is always greener thing. But unlike Isabel, I've had plenty of times when I can't find what I really need, especially when I'm in a hurry. You often have to make compromises especially when you're on a budget, but when you can't find what you're looking for and settle for something you wouldn't buy under other circumstances, it's really annoying. So I've tried to get better at planning ahead so I can make decisions decisively and take advantage of the scores I do run across.
It's a balancing act, though - anything that I choose means that I've spent that amount of my budget and can't spend it on something else that may become available in the future. I track my clothing budget by quarters, and I try to focus my buying in the first half of the quarter for the current season, and shift to the next season for the second half of the season. (The biggest deals are usually way out of season, though, like winter for summer or vice versa, 6 months off, not 3.)