A scene should do something. That's all they're there for.

Do your scenes accomplish anything? For example, they could drive the plot forward (e.g. Killer stalks his next victim.) They could reveal character (Killer has a talk with his girlfriend about killing an annoying mouse in his apartment, but the readers know he's talking about his victim.) They could give the reader an emotional high (Killer kills, inciting terror; or, if it's a black comedy, Killer fails spectacularly to kill the victim, inciting LOLs.)

Scenes shouldn't be *just* exposition dumps (Killer sits on a fence remembering why he's going to kill Victim) or explanation of things that really don't need explanations (Killer goes shopping for knives, duct tape, etc. just so the reader knows he has them, when the reader really doesn't need to know that at all.)