Generic parts are a gamble, plain and simple. My last pump seal from a no-name brand gave out in half a year. The factory part it replaced went for five. You save cash at first, but more breaks mean more hassle and cost. For something you use all the time, spending a bit more now avoids trouble later.
Replaced a thermostat last winter with a cheap one from the auto parts store. Thing started sticking open after two months, left me with a cold house on a Tuesday morning. Had to take the whole day off work to do the job all over again with a better brand. Makes you wonder where they cut corners to sell it for half the price.
Honestly, it's not just about the parts being cheap. Sometimes the store itself has no clue how long that junk's been sitting on the shelf. Tbh, a thermostat with old grease or a dried out wax pellet is gonna fail fast no matter what. You pay for the fresh stock and the warranty you get with a known brand. Ngl, seeing that happen on a Tuesday morning is the worst kind of luck.