I agree with pp who said that it mostly depends on your washing skills - and good reminders about the saponification process using up the lye. Think about the material of your tools as well- a glass bowl is much easier to clean for safe food use than a plastic bowl would be.
That being said I personally did buy* a separate set of tools mostly because it's not that expensive. I bought a $27 Cuisinart Hand Blender in pink so there is no confusion and bought the rest of my tools from the dollar store like mixing bowls and spatulas (I confess I did also buy 3 nice pour spout containers off Amazon when I ordered my mold :))
Good luck! edit: forgot a word*