Carry Over

I can’t carry over vacation days from year to year, so I end up using a bunch of them at the end of August and beginning of September.
I’d rather use them in October or April when the weather is nice, but my work anniversary is in early September.
I could use those days in October or April, but what if I need time off between April and September?
I don’t want to chance it. So, I save the vacation days up.
I thought about quitting and getting rehired in late October.
But I don’t want to chance that either.