If it works properly, I rarely worry about equipment. If the sound becomes intermittent, like some pieces that regularly had to have the controls & switches cleaned, I clean them. It might take some time for me to be motivated to do it, but it will eventually be done. In the process of that now. If there's an obvious component failure, I don't wait unless it's NLA or too expensive. If it has tubes, like my guitar amps (two are from the late-1950s, one is from the late-1930s), I just do it.
I really preferred having local shops where I knew who would be working on my stuff but many places closed, people left the business, retired or died.