PIM backup is for sure the way to go. I use it all the time.
Also, if you want, when you fix your phone, or get it fixed, or get a new one check out Microsoft
MyPhone. It automatically backs up your contacts to an online server at any time schedule you specify so if you have any problems with your phone, your contacts will be safe. It also backs up texts, pics, and other things too. The service is free and it saves you the hassle of having to save your backup manually.