The trap in a sink drain line has some key functions. Not only will it catch the wedding ring or anniversary earring that slips down the drain, but it also creates a place for a water block to prevent sewer gases from coming up the drain line and into the house. For all the good a trap does, it’s vulnerable under the sink and can be knocked around easily by cleaning buckets and stray bleach bottles. This bruising can lead to leaks and hundreds of dollars in water damage.
Replacing a trap is something you can handle yourself. It’s a straightforward plumbing task that requires a minimum of materials and can be done easily in an afternoon. If I’m replacing a trap, I always add a cleanout if one is not there already. A cleanout is a code requirement in many areas, and it will save you a big headache if the drain line ever gets blocked.