The answer to your first question is a battery pull is the time honored reboot to fix or resolve minor issues in event of a malfunction. They are the manual recommended cure for many of the things that can go wrong.
Posted from my CrackBerry at wapforums.crackberry.com
BK is absolutely right. Anytime you're BB doesn't act exactly right, pulling the battery almost always fixes it.
And, as far as turning off your BB, it doesn't matter if you do or dont. When I first got mine the girl at verizon said I needed to turn it off for atleast an hour every night but I quickly found out that's unnecessary.
Posted from my CrackBerry at wapforums.crackberry.com
I do it about every three or four days, just take out the battery for 10 seconds or so and re-boot it. Also idk how much you text but if your SMS in and outboxes are full deleting them occasionally also helps if you're having speed issues