Shingle replacement is not a topic that many people think about that often, but if you want to learn when to replace shingles you are going to need to think about it at least once in a while. Shingle roof repair is a very important do-it-yourself topic because the roof of your house is arguably the most important part. It protects you from the elements and it ensures protection for the rest of your house from normal wear and tear. Learning to replace roof shingles first requires knowledge about when replacing roof shingles is appropriate. In general terms, replacing shingles should be done every 20-30 years assuming you do not repair shingles in between, but there are ways to get far more detailed in knowing exactly when to replace shingles that have worn themselves out.