I don't think a compressor is a must have for DIY but it certainly is nice to have. I have all (well I suppose most but certainly more than the average DIYer) the normal mechanics air tools but find reaching for them most often for woodworking/construction. Bought a needle scaler last year that has been a great tool for restoration projects, etc. Beyond obvious uses, they can also be used around the house, e.g., blowing out sprinkler systems, etc. I have three compressors: a pancake, 30 gallon portable and 60 gallon fixed and each of them get used all the time.