Whether people like to admit it or not, one thing that can help Lightroom performance when it slows down is a restart. It can also help when Lightroom does something unexpected or unusual. I’m not implying that Lightroom is an unstable mess, but when it’s be actively running for days, through sleep cycles, it might need a refresh.
Years ago in response to a cry for help from myself as a developer needing quick restarts for testing, Matt Dawson from The Photo Geek wrote a script that restarts Lightroom quickly. I mentioned it back then, but because I’m using it regularly, I think a timely reminder is in order for those not familiar with it. Yes, it does work with Lightroom 3!
The install procedure is well explained in the post. Big kudos to Matt for doing this.