This answer is a bit confusing. The questioner asks if renewing a month earlier than the expiration date will restart the clock on the new year of membership at the time of this one-month-early renewal or will add 12 months of membership onto the end of the existing expiration date.
I'm sure it must be the latter, but this answer does not clearly say so.
For subscription products (unless duplicate subscriptions are enabled), they would not be able to renew early without completely cancelling, otherwise they will get a duplicate subscription error at checkout. For one time products, if they renew early, the renewal calculation will be based on the date of the renewal checkout, not the original checkout. I hope this answers your question more clearly.
Well, that is quite a surprise to me. And I feel confident that this is directly the opposite of what most anyone would expect.
What this means is that whatever time remains between the date of your renewal and the end of your current membership will be lost. I've never heard of a membership payment process that works this way. The only way for a member to avoid losing the value of their paid membership is to renew only at the very last moment.
If you don't mind, could you tell me why MemberMouse doesn't simply add the renewing duration on to the end of a current member's subscription?