I agree, regular water changes are the most important part. As long as you're doing that you should be fine. Although if you ever see a good deal on a spare heater or filter, it's not a bad thing to have an extra on hand. By the time you notice one has broken, it may have been out for a few hours already, so it's nice to be able to just plug the new one in rather than driving to the LFS. These things always seem to happen to us at 11:00 p.m. on New Year's Eve.