Expected Weight Regain Post Op

I am four months post-op and steadily but slowly losing weight. I have read in several places that we can expect to lose 50% - 60% of our excess weight. The challenge with weight loss is clothes - when do you know you have reached a size where you will stay? I have read in the same literature that after we reach our lowest weight loss point, we regain 10% - 20% back. It is my understanding that initially we lose too much weight but our bodies find a way to find an optimal weight. Apparently we will lose weight for up to one year after surgery. And as time passes, it will slow down considerably,

Is this your understanding as well?

If you are more than one year post-op, do you find yourself continuing to lose weight? When could you stop buying new clothes?

Should I keep some of my new post-op clothes in anticipation of a 10% - 20% regain?

The reason I am asking is that every time I hit a plateau, I tho I, "ok, now I can buy new clothes." But a few weeks later I lose 5 more pounds. I have no choice but to buy new clothes because the old pants literally start to fall off when I walk. But that gets expensive. My shirts seem to work fine, though the collars are too big, but suits, jackets and pants have to be altered and/or replaced.

Thanks in advance for any insight that anyone can offer.

I wish everyone success in his or her weight-loss journey.