I've often thought about giving a one month option and a three month option (quarterly) and yet I haven't really seen this in SaaS... do you think there might be some people who would prefer to only worry about it once every three months?

It's the worst thing you could possibly offer.

Customers will notice a "large" bill every three months. It's just infrequent enough that they don't remember what it was from 3 months ago. It's just large enough that they really want to check where the hell is all that money going to. Customers will investigate and that can only result in cancellation.

A monthly subscription is designed to be easily approved by a middle manager (and fly under the radar). A yearly subscription is designed for customers who plan ahead or cannot do recurring payments (recurring invoices/approvals is a huge pain to deal with).

I found this really helpful, thank you!