A tankless often comes with the house. Somebody installed it two owners ago, and nobody since has had a reason to think about it. It just runs, until the day the hot water starts cutting out or a code you've never seen shows up on the controller.
In La Mesa, the likely reason is scale. The water here is hard, and years of it running through a unit that's never been descaled leaves the heat exchanger coated. The unit runs hotter than it should until it starts shutting itself down.
Someone comes out, checks the unit over and tells you what shape it's really in. Sometimes a descale and a part get it back on track. Sometimes it's time for a new one, sized to your household. Either way, you'll know where you stand, and the decision is yours.
