What's a decent amount of backpacks to have?

I got:

tote/grocery bag
messager bag
laptop bag
casual backpack
school backpack
dayhike pack
internal frame backpack (30L &50L)
external frame ALICE pack

Also, Does anyone know if Jansport's Megahertz pack holds up? I bought one because it came with a laptop sleeve and it feels REALLY flimsy compared to other cheapo backpacks