let me ask how much MikroTik's hardware usually has a lifetime.
I use other firms to find it very fast, so I want to consult people. thank you

If the device works, most likely it is fine to buy used, as it will work for a long time. We still see a lot of RB133 and RB532 in operation, which were released/made more than 10 years ago.

In most cases where Mikrotik HW failed, it have always been due to damage from thunderstorm or similar disastrous event.
In remaining cases it was all due to bad capacitors on board that bulged and had to be replaced. This happens mostly on RB4xx series.
After replacing them the board continues to work and probably will for years to come if you use quality capacitors.
Other way how HW might die is due to too high flash writes, so just don't do certain stupid things with scripting and logging.
Too bad RB532 is not supported anymore, there are many available on used marked. At least latest LEDE still runs on it perfectly fine...

hi Root, no issues on my units but I use a proper UPS for electrical shenanigans.