Monday closings
 

Which one of these towns should we avoid on Monday due to closings?
Lisbon/Belem
Evora
Tomar
Sintra

I would think it would depend on what, exactly, you want to see.

Exactly. Monday closings are very common all over Europe, but what is it you're worried about? If it's museums and historical sites, check the websites. If it's shopping, depends on what you're shopping for. If it's food, you're always going to be able to find it.

And what time of year are you traveling? Here in rural France there are constantly changing hours and days of openings, depending on the season. Even if you live here, it's impossible to keep up with. When are you traveling?

As a general rule, though, in many/most parts of Europe, Monday afternoons are kind of a half-dead time.