How do professions work in terms of exp lowering / reseting after level 10?

As the title says, despite all my looking I haven't been able to find ANYTHING on the subject.
2 main questions about it

1.) How often must I craft something to keep from losing exp.

2.) If I DO lose exp, does it just completely reset me back to 10, or I do lose a set amount of exp or something?

it says that i need to do stuf around my level so uh i need to do lvl 130 stuff? and did they changed something on the recipes? i did a pendant that says one time only craft and after i did it i could do it again.