Don't avoid "since"! You wouldn't advise any such behavior from those of us attempting to learn Spanish.
I guess that I would use "since" in the sense of the beginning of something that is ongoing:
- Cranberries have been in the markets in Mexico since 1995 when they were a prop in a popular movie.
- Joe had been smoking since he was 13 years old. But when he got lung cancer, he stopped cold turkey.