My video courses (tech courses on programming / ops) are a one time purchase and I offer a 1 year money back return policy, no strings attached. The only reason I even put a time limit on it is because without putting one, then it's not clear on how returns work or would require too many words to describe a lifetime return policy.
I'm a developer myself and having a 30 day return policy for information seems like a high pressure bullshit tactic. People live busy lives and trying to force someone into watching a 10 hour course RIGHT NOW otherwise they can't get a refund later on feels dirty.
In other words, I optimize for the happy path. I want to focus on making the experience as good as it can be for people who are interested in learning whatever topic they signed up for and aren't the type of person who will buy it, consume it and then return it.
The dishonest person who will buy your stuff, consume it, and then ask for a refund will do that with a 5 day, 30 day or 365 day return policy. That's just the type of person they are.