Can you replace springs yourself?

You can replace garage door springs yourself, but the answer depends on the type. Extension springs, the long stretched springs running parallel to the horizontal tracks, are a reasonable DIY project. Open the door fully, clamp it open with vice grips, then unhook and swap the springs while they are slack and unloaded. Torsion springs, the wound springs sitting on a shaft above the door, are dangerous because they hold their tension even when the door is closed and require properly sized winding bars to safely release. Wrong-size springs or improvised tools cause serious injuries every year. If your door uses torsion springs and you do not have the correct bars and matching replacement springs, hire a pro.