Can you replace garage door springs yourself?

You can replace garage door springs yourself, but only safely with the right tools and the right type of spring. Extension springs above the horizontal tracks are the safer DIY job: open the door fully, clamp it in the open position with vice grips on the track, then unhook and swap the springs while they are at rest. Torsion springs above the door are under extreme load even when the door is closed, can release with enough force to break bones, and require properly sized winding bars and matching replacement springs. If you have torsion springs, no winding bar experience, or any uncertainty about the door weight or spring size, hire a professional. Always replace both springs together.