1. It should last indefinitely. Use the right materials, use the right techniques and sequences. Example: Some caulks will only last six months in a particular situation, such as around a shower. For an extra $2 a tube, why not use caulk that will last six years?

2. It should look like it was always there. A repair or addition should not look "added on". this is not always possible within a given budget, but it is always the standard.

3. It should be practical. It should work well and not introduce new problems.