Most dental plans suck. GIC's dental insurance (state employees plan in Mass) has a $1000 per family member maximum coverage.
A root canal will cost $1000+ out of pocket, and that's if you haven't had a cleaning and a filling in the claendar year.
What they consider "usual and customary" for dental work hasn't changed since the 1960s.
Our vision coverage isn't much better, either. I just pay for my glasses out of pocket at Costco, rather than settle for the cheap-assed frames Davis Vision allows me
