Picasso Museum

At least an hour. Probably no more than two.

I agree with the previous poster. It is so well designed with a natural flow, it is to be enjoyed at a normal pace.

Then find a snug little place nearby and have come coffee.

We were at the museum last month. The special exhibit is small, I believe it was two rooms, one on either side of a hallway. It was a nice exhibit which we enjoyed, but you could see it well in a half hour. How long the museum takes depends on your interest level. You could spend an hour to an hour and a half and see it thoroughly. We bought tickets on a whim, as we had been to the museum before. It wasn't busy at opening time on a Sunday morning and we walked right in. We have spent several weeks in Barcelona, and our apartment was close to the museum. It was interesting to look at the lines every time we passed by. Guidebooks talk about how it is always mobbed, but there were often no or very few people in line. Still, if I was only in town briefly, and didn't have the luxury of returning easily at another time, I would book ahead to be safe as we did occasionally see a long line. We also encountered more than one tourist asking for directions to the museum on a Monday when it is closed.