MacBook hard drive swap: suggestions?

I am working with my late 2008 MacBook 13". Since I bought it new, I have upgraded the HD to a 500GB disk, and added/upgraded the RAM to 4GB. It’s currently running OS X 10.7.5 (that’s as far as Apple will let me take it).As to be expected, cruft has built up over time. I am running the Disk Drill utility, and it is telling me that I have some hardware issues on my HD (bad sectors, I think), and that I need to prepare to replace it soon. I religiously use Time Machine to back up to an external 500GB drive, but I’m wondering if I might not be better off (re)starting from scratch, reinstalling the OS and only the software that I use regularly.What are your thoughts on this? Would it be better to just pull everything off of my current Time Machine archive? I’m willing to put a little extra time and effort into a reinstallation of the OS and software if it will result in a performance gain.Your thoughts and suggestions are welcome; thanks in advance!

A clean installation from time to time is good for the computer. Basically because you get rid of all the extra lines in the registry of the computer after installed and uninstalled so many programs. Now, is it worth it in this case? It depends on what you think and how slow it is going now.

If you are developing bad sectors, it will only get worse. Reinstalling will not help since that is a physical hardware problem that no software can fix. Backup your data, install a new hard drive, and install the operating system on the new drive.