Most newer cabinets have self-closing hinges that hold the doors shut. Others have magnetic or roller catches. A catch that no longer keeps a door closed is either broken or out of adjustment. Catches are fastened with two screws, so replacing a damaged catch is simple. Adjustment is just as simple, but you might have to readjust the catch a couple of times before you get it right. Loosen the screws, move the catch in or out, and tighten the screws. If the door doesn’t close tightly, try again.
How to DIY it: This job can be messy, so protect nearby surfaces by covering them with plastic or cardboard. Spray the springs with garage door lubricant (about $7 at home centers). Don’t use oil, grease, or other lubricants. They may be cheaper, or you may have them on hand already, but they won’t work as well and tend to pick up dust and grit—just what you don’t want on moving parts.