I personally don't like filling bag right to the brim.
I might as well answer the question now ~
When I used to use my Turbopower 1000 as my daily (vacuuming about every 2-3 days) when my hair used to be long,it usually filled up within a week. Now my hair is stupidly very short,it usually takes about 2 weeks.
With my Sebo X1.1 (my new daily driver) I can't say yet as I've only had it just over 3 weeks,but already it's quarter filled but I know I can fit alot more in.