Sluggish performance, 2008 MBP

Question

My wife's 2008 MBP has been acting sluggish for a long time (the last year or so, I'd say), and it's gotten worse recently.  Yes, it's an older computer but I think the performance is disproportionately slow, particularly given how simple her computing needs tend to be.  Here are the specs:
13" MBP model 5,1
2.4Ghz Core 2 Duo
2 GB RAM
250 GB HDD (about 60% full)
OSX 10.8.4
And the programs she runs most of the time:
Firefox
MS Office 2011
Calendar
iPhoto
Preview
She has some more intenstive programs (such as Adobe CS6) but doesn't use them on a daily basis.  Typically she'll have only a few applications open at a time, sometimes several browser tabs, though.  The computer often hangs up with simple tasks such as opening a new tab in Firefox (regardless of how many tabs are already open) or even just opening a new Finder window.  Opening most files and programs takes a while, really.  She'll get the spinning wheel of death and have to wait several seconds for the task complete, or in some cases force quit one or more applications in order to get unfrozen.  The situation is a little better after a fresh reboot, but not much.  I've tried some standard maintenance--repaired permissions and verified the disk, defragged the HD once, all with negligible effect.
Can anyone recommend additional troubleshooting steps?  Thanks.

Answer 1

Each successive major release of OS X has weighed your machine down with more resource demands. On top of that, you likely have a very fragmented file directory. Heed the really good advice about increasing your RAM.
The more fragmented that file directory becomes, the longer it takes the operating system to locate files on your hard drive. I would recommend using Disk Utility to verify/repair your permissions, and also verify your hard drive is healthy. This alone will not fix your file directory.
Follow these instructions for booting your machine into Safe Boot Mode, and why this is beneficial. I do this about once a month as routine maintenance. Beforehand, I move the contents of my local Library/Caches to the Trash. Once I have booted up in Safe Boot Mode, I empty the Trash, and then reboot normally. You will likely notice an improvement, but not one that overrides the RAM upgrade recommendations.