Does every Computer case have a spot to put a case fan?

If so how do you know what size fan to put in it.Does every Computer case have a spot to put a case fan?
Of course, Size: 80mm x 80mm x 25.4mm.Does every Computer case have a spot to put a case fan?
Yes they have to (unless you custom build it), it is not good for a computer to get hot (VERY VERY BAD). and if you do custom build it I would still advice putting atleast one fan in it (mine has 5 fans)
Yes, the good ones would provide multiple mounting locations - front, back, and on the side panels.





They are either 80mm or 120 mm. Just check the mounting holes. Make sure you mount them in the correct direction - depends on where they are mounted. The fans will come with screws and some with neon leds.





Get a good, reputable brands - the cheap ones can be terribly noisy.