A single-car residential door, done right, is not a weekend job for most homeowners, and a double door is worse. The panels alone are heavy enough that a slip during hanging can bend track or crack a jamb, and torsion springs used on doors from the 1983 median build era store enough force to break bones if you wind them wrong. Where a DIY attempt makes sense is cosmetic work - repainting an existing door, swapping hardware, adding weatherstripping. Where it doesn't is anything involving spring tension, track alignment, or opener mounting on framing that's decades old and may have settled. If your opening is out of square, which is common in the older housing stock around here, you need someone who can shim and level as they go, not just follow a set of instructions written for new construction.