That's a roll of the dice. But I do know folk that do this and carry on.
Try just the SSD and new battery first. You may be surprised.
Hi guys, I just got into my possession a MacBook Pro mid 2009 13 inch core 2 duo processor. The battery only lasts for about an hour and it has 4 gigs of RAM and 250GB of a very slow hard drive. I was thinking of spending the close to $150-$200 to upgrade to SSD, get 8 gigs of new RAM, and a new battery. I currently don't have a laptop now and don't want to spend a lot of money. Do you think it would be worth it? Would it last for a couple more years?