I finished a nine-year project of mine this weekend, having visited 49 museums. That’s every museum in urban Stockholm that is currently open, as well as a few that have since closed or that are only open to groups by appointment. Several of the ones that my wife likes I’ve visited multiple times. And I’ve also visited 20 museums in more peripheral locations outside of town. This may sound like a lot, but it’s little more than one new museum every second month on average.
I really recommend this kind of project! You get to see amazing things if you quit going back to the same ten museums year in and year out. Wikipedia has a convenient list for most major cities (here’s the one for Stockholm that I’ve used). Paraphrasing the famous Dr. Jones, you belong in a museum!