I live in Spain in a 85m2 [1] and it isn't cramped in term of room sizes. In fact my 2 daughters decided to live in the same bedroom which meant I could convert one to an office since I am working remotely. Having said that 100m2 would give us access to a second bathroom which would be nice considering there are 3 girls living in the same place. 150m2 would be overkill for 3 bedrooms, I guess it would be more a space for 4 bedrooms or 3 bedroom and a dedicated office.
[1] caveat is it is not an appartment but a townhouse with a commercial space in the main floor. It give me exclusive use to another 85m2 rooftop space with a washing machine there so I don't have to dry clothes in the living room + exclusive use of the stairway where I store our 8 bicycles and the standup paddle. But I would say that if I didn't have those extra space I would just not have so many bicycles and things and would hang the clothes to dry hanging at the windows like everybody does.
[1] caveat is it is not an appartment but a townhouse with a commercial space in the main floor. It give me exclusive use to another 85m2 rooftop space with a washing machine there so I don't have to dry clothes in the living room + exclusive use of the stairway where I store our 8 bicycles and the standup paddle. But I would say that if I didn't have those extra space I would just not have so many bicycles and things and would hang the clothes to dry hanging at the windows like everybody does.