Unfortunately when you find and repair leaking roof, the roof may not be the culprit. There are other Building Materials Reclamation Yards parts and structures that are put on a roof that might make the repair leaking roof a real puzzle.
It may be easy to think that if you see broken or missing shingles then the repair leaking roof project will be fairly simple. But again this may not be correct. Water may move in a different direction under roofing tiles or shingles and then drip or leak away from where the actual roof damage is causing the leak.
Generally if you have a leaking ceiling or attic roof then you should be able to go up on the roof to inspect it. Although there are many people who are afraid of heights and will call in a roofing repair specialist before they climb up on a ladder then onto the roof.
Another consideration if you are going to walk on your roof, remember you may be causing further damage because your weight may damage the shingle or tiles or what ever the roofing material is. A roofing specialist knows where they can safely walk on a roof to inspect it. An experienced roofing specialist is also familiar with roof problems and can probably see where the problem may be with little effort. Unlike the home owner who may have never even been up on a roof before.
Also that leaking roof problem may not be in the roofing material but in the flashing that is around roof vents, sky lights or other structures that sit on your roof. In some cases if the wind is at a particular angle it can actually blow up under the roofing material and blow in a stream of water. In this case you actually do not have a leaking roof at all. Chimneys also tend to make it appear that you have a leaking roof.
If there are loose shingles on your roof they may be the cause of the leak. You will need to determine if the leak is in the same proximity as the damaged White Roof (Cool Roof) shingles, if so then get the damaged shingles replaced. In any event, you should always replace damaged shingles so you prevent any future roof leaks.
So you also need to investigate where any flashings are attached. That may be your problem but the repair leaking roof puzzle is a difficult one.