I work in the public sector, and in my experience terms and conditions still bear culpability. If your clients want you to sign their PO because they don't want to deal with contracts and their legal team, and it has terms and conditions, then I would consult your leadership or legal team. Maybe one of them could sign it.

At the same time, even though the contract process is a little laborious, it may be worth it to prevent redoing things every year. You could ask you clients if they have a standard purchasing agreement that you could sign (pending your organization is OK with it). That makes the process usually pretty speedy.

I always focus on the customer experience. I also focus on culpability. Therefore, my happy medium is usually to communicate how valuable our clients are to us, but that a contract is the more secure, and convenient option (especially since you have licensing renewal requirements annually). And then I do everything I can to make the process easy for them.

-Diane