A good question.

Skill level is going to be down to experience in general, but obviously there will be exceptions to that rule. I began specialising in modelling years ago, I could make generally good clean meshes, but my biggest problem was my initial observations of things.

Some people can grasp things quicker than the next guy, and unfortunately thats life so I would compare your work against other peoples, check out therir show reels and see what level they are working at and decide where you stand.

Despite being a senior Modeler, I see other modeler reels that knock my worjk into next week and these guys dont even work in the industry but are busting their balls to get their work out there. I do wonder why they arent in good positions workwise, it could probably be down to inexperience....its a catch 22 situation