Screens take more abuse than any other part of the door, and they are the cheapest thing on it to put right.
If the frame is still square and the rollers are fine, rescreening is the economical answer. We strip the old mesh, replace the spline, and fit new material tensioned properly so it does not bag out in six months.
Once the frame itself is bowed or the corner keys have let go, a new frame is the better value. Screen frames are thin extruded aluminum and they take a beating from wind, pets, and being shoved by people who could not find the handle. A rebuilt frame with proper corner hardware simply lasts longer than repeatedly straightening the old one.
Screen doors have rollers too, and they are usually little plastic wheels with an adjustment screw. When they wear, the screen drags on the sill and the frame starts to rack, which is what eventually kills it. We replace those rollers as part of a screen job rather than fitting a good new frame onto worn hardware and letting it fail the same way.
We also check the screen track itself. It is shallower and softer than the main door track and it packs with debris quickly, which on its own can make a perfectly good screen feel broken.
Worth knowing: screen doors are made to order to the exact opening. There is no standard size that fits every home, which is why a big-box replacement so often ends up leaning against the garage wall.
Free onsite estimates, same-day repairs, every day 7am-9pm.