We have carpet that we want to rip up. We want to have the floors
sanded and finished.
It's strip floorimg - about 45 years old and seems to be in good
condition judging from the
corners of the carpet I lifted up.

It's about 800 square feet to be done. I've had a few people in to
give estimates.

Person 1 wants to put down an alcohol-based sealer and then 2 coats of
oil based polyurethane.
He'll put a third coat of poly if I want him to (another 30 cents per
SF) but says it's not necessary.

Person 2 wants to put down three coats of oil-based poly and doesn't
use a sealer. He says he used to use it
and stopped because's he's learned over the years that the problem
with a sealer is that over time, it dries up and crystallizes and
causes the polyurethane to flake off the floor.

Both people came highly recommended and both do nice work. Prices are
very similar so there's not much differene there.

Which method is better? Which is more durable? Does anyone have
experience with the sealer after say 10 to 15 years? Does it really
flake? Also, is 2 coats of poly over a sealer as good as three coats
of poly with no sealer?

If it makes a difference, I'm on Long Island (NY) about 3 miles from
the Atlantic Ocean.

Thanks!