Actually I did change it to 3 years and that is when the board starting having problems. The old software did not do FULL TEXT searches according to UBB. This new version does but if you have a few people doing these searches on large periods of time the tables lock while the search is happening. Not bad when only a few people on, but if there are large amounts of users the board will crawl.
 
For now just keep in mind what you want/need to search for and adjust accordingly. It might have been coincidence but for now I will leave the search date as it is. Let's get some more days behind us where the board keeps working well before customizing too much.