Museum visits were a part of my kids' childhood/homeschooling, we love them XD
Unfortunately for the bigs unless we had gone in a group with multiple adults who could supervise individual subgroups, our visits tended to be dictated by youngest's attention span as while the big two could concentrate for lengths especially once they learned how to read and wanted to read at least some of the signs, youngest's adhd meant he wanted to see everything all at once right this second and all he wanted to do was rush to the next exhibit after seeing the first one. When they were younger we could cover the whole museum (or zoo when we went to the zoo) in the one trip, but as they got older and youngest got a longer attention span or at least the patience to wait til his siblings were done, we ended up spending a lot/all the time in sections of interests and less time/none in sections that weren't interesting at the time.
Those membership cards were so worth it purely for that and not feeling like you had to drag out the trip "to get your money's worth".