Thou shalt reuse, thou shalt not rewrite
If the same piece of code is repeated at least once, question yourself why and try to avoid it by creating a reusable routine. If there is more than one SELECT for the same table in a program, make sure you can’t merge them into a single one. Sometimes a smart use of RANGEs to unify parameters can avoid the need for multiple SELECTs. If the same code is used in 2 different programs, don’t repeat the code.