Monthly is the default and it is deliberately easy to leave; annual terms with the procurement paperwork enterprises need are available when you need them. The product's retention plan is the compounding brain, not the contract.
Early-stage honesty: pricing mechanics beyond the published $300 plus 5 percent get worked out per customer, quickly and in plain language, through the waitlist conversation.
The philosophy holds regardless of term: a memory that gets more valuable every month should not need a lock-in clause to keep you, and your data exports freely either way.