OP are you doing work for hire? i'd agree with what ralph suggested unless you are doing assignments .
some clients REQUIRE that you have a certain amount of insurance or they won't allow you on-site.
i didn't have insurance until one job required me to, and they i kept it until a few years back, and then
i took an assignment recently and had to get it again. i'll probably renew it in the summer.
often times replacing large format equipment isn't too expensive, especially since no one wants film gear anymore, and you might be able to replace your wollensak optar
with a schneider app-symmar for what you originally paid for the optar. and if it is vintage glass you are hoping to insure
like a pinkham smith visual #4 knuckler, good luck, it will probably be harder to find the lens than paying the deductible and getting the check.