The altima uses a timing chain, not a belt.
start back at the battery, are the leads corroded? is there a clicking noise when the starter is engaged but the starter wont turn? are the leads from the battery to the starter in good condition. Usually any sign of a white powder around the battery or a lot of dirt is a sign of needing attention. The clicking could be a starter relay aor the starter itself needing replacement.
You hear noises coming from the alternator. The dash light for charging stays on. If not equipped with light might be a guage, in which case you see it not charging.
it looks as if there are small cracks on the pulley side of the belt. If these are within 1/8" of one another you need a new belt NOW
you will hear a rumbling or wining as you drive, especially at speed
Check to make sure your battery's charged up and the connections are all clean. If that's the case, then your starter's probably showing its first signs of laying down. Same thing went on with my Prelude, ended up just putting a new starter on it.
water mixed in oil, check dipstick, looks milky in color. quick overheating. visible leaks around head gasket.
hopefully you will be installing a new starter...
A slow crank or excessive power draw. Make sure that your battery is in good condition before condemning your starter.
perhaps because the new starter is doing its job.... You think maybe it's supposed to start with the new starter in it?
on the starter
No, just the opposite. A new starter will require less power to turn over than an older starter.