How often do the borders of a school zones change?

I'm sure those with more insight can weigh in, but there is no set time period. You can look to the neighborhood and see when it was last changed or how crowded it is now, which might force a change. Also, don't get hung up too much on one school, for example PS 158, 183 and 267 are all quite good, although one might be "better" based on rankings one year. You should check out insideschools.org and urbanbaby.com for more on schools.

You can volunteer to improve whatever school your child winds up being zoned for. That's how "good" schools became good.

What is your "background"?

Rezoning is completely unpredictable. Therefore you have to ask other parents in your desired school if there has been any talk of rezoning or any such recent history. In Lower District 3 this can be an issue, but of late only regarding PS 199

> Rezoning is completely unpredictable.

Not really. AVOID elementary school with LONG waiting lists and overcrowding. The shrinkage of PS 87 was totally predicable due to this. And now it's the turn of PS 199.

Basically parents kick and scream about their rights and the fact that their zoned school shouldn't have a waiting list. In PS 199, this happened enough though just a few blocks away PS 191 has been underutilized for YEARS. Hence the rezoning.