This really depends on your job situation, family situation, age and so on.
When we were first married we had sex almost every night. Once the kids came along it was less frequent. Then there were major family illnesses and death.
When we both retired we thought we had it made. We were going at it like when we were first married. Then it changed. We had to deal with the ravages of time: erectile dysfunction, menopuse, high chlorestol and hyperntension, cancer scares, major operations, and the general aging process. This was coupled with the breakup of one of our children's marriages (husband abandoned her) and her medical problems.
So today we have sex less frequently then we would like but we enjoy it as much as if we were again newly weds. To paraphrase Winston Churchill - No matter what your problems, "Keep on fucking on." Or as they say at the gym, "Use it of Loose it."
So I have checked off several times a month.