How do I know I'll need a full tower case

[UnicornFluff]

I already have a mid tower but I want to know, is there a specific way to know if you need a full tower case, or is it just a preference?

 

[Tradesman1]

Mainly preference or especially if you have a ton of drives, most decent mid-towers will run SLI/Xfire (x2) going to 3-4 GPUs a larger tower would give more room to work around in and more open space for better air circulation

 

[badra100]

If You have many specs of CPU, then You will need to full tower case.