I only work on the products I've built myself. Bug fixes are always free, even if the project has been delivered years ago. Trivial changes are sometimes free i

I only work on the products I've built myself. Bug fixes are always free, even if the project has been delivered years ago. Trivial changes are sometimes free if I have a good relationship with the client. Mostly I group the work for a day and charge my daily rate. For the 2nd question, if it's a fixed budget project, I bear the cost myself and take it as a lesson for the future to do estimates better. If it's not, I always inform the client that it might take a longer than the estimates if it's not something I've done before.