We stock standard torsion springs, cable sets, rollers, and hinges sized for the double and single doors common across the service area's newer construction, which covers most of what shows up on a Fulshear call. Insulated steel panels in the sizes that match post-2015 door kits are the other thing we carry as a rule, since that's the panel type on most houses out this way.
What we don't carry on the truck: panels for a custom or architectural door, or parts for an opener model that's been discontinued for years. Those are special-order, and lead time depends on the manufacturer, not on us - something worth knowing before you count on a same-week fix if your door is anything but standard.