i think it can be a great motivator, so long as you make sure and keep it as motivation.
make sure you dont fall into a trap of having those clothes make you feel bad, because you dont fit into them quite yet.
personally i had a pair of pants that i had waaay grown out of. for the longest time i couldnt even button them and while i got rid of all my other non fitting clothes (both as i got bigger, and as i got smaller) i always kept this one pair. When i was heavier, i would try them on as motivation, to see as they started to fit and to remind myself why i was passing up desert.
and now, i like to try them on to remind myself how far ive come, and how much leaner and healthier and thinner i am now than i used to be. eventually id like these pants to literally be falling off me, but im still working on that.
my newest goal is to be able to wear a bikini top during summer, something i have literally never done before. so today i bought one. it makes me feel fabulous, and makes me motivated to look fabulous.
so yes, i think buying too small of clothes can be a great motivation to lose weight and keep going, just makes sure that it is a motivation and dont let yourself be discouraged by it.
You are buying it knowing that it doesnt fit now, but confident that one day, it will fit
