Drain washers, gaskets, and o-rings are often the little culprits behind bigger plumbing issues. They break easily, can get twisted or misaligned without much effort, and are easy to forget about when putting an assembly together; fortunately, these little devils are inexpensive and easy to replace. Stock up on a few washers, order an extra gasket or two, and keep plenty of o-rings on hand for when you (or your customers) spring that next leak. All it takes is a little know-how and the right parts to keep the drain working properly.