I have had my MBP since the summer of 2010 and I just ordered an SSD (http://www.samsung.com/us/computer/memory-storage/MZ-7PC128D/AM) for it just because I thought it was time for a slight upgrade. Since I will be installing a completely new piece of hardware into my beloved machine I wish to keep it as clean as possible of junk files and folders and whatnot (also I am going from 250GB to 128GB, so I would like to keep on top of it to save as much space as possible). This was my first Mac and I tried to keep it clean from the beginning, but as I was new I probably let a few things fall through the cracks. I have been doing a little research and have been using AppCleaner for quite awhile to uninstall items, but as for clearing out old files from apps that I have already deleted I have no idea? I just downloaded and ran/used Disk Inventory X and it seemed to work. I was thinking about buying MacKeeper, but from what I have read it is mostly targeted towards scared Windows converters (like myself) who worry too much (again, myself) I was wondering if MacKeeper is worth the $38 or not or if there is a free app that is just as effective? Thank you so much!