Short answer is: You Don't.

You don't keep them "for life."

Typically the term is 3 months.

BUT

The fact that your site is about education credits is a potential game changer. I've never seen or thought about this topic before, and it's a good one.

You really may have a chance of getting very long term customers with this one. They have a big reason to keep coming back.

I've worked in the nursing & Safe Patient Handling fields and with the operator of a professional organization in the field.

Your biggest problem is how to let enough people who need CPD credit know you exist.

There's an annual deadline for these things, isn't there. I've seen letters for my in-laws not-so-gently reminding them the education credits need to be earned to keep their status in the professional organization.

So you can do something similar. Letters, postcards, even perhaps partnering with the professional association. They may have "fairness" rules against that, but it's worth trying.

Are there forums GPs hang out in? Advertise there. Not once. Consistently.

Your advertising copy is pretty easy (for me, anyway) to write:

> 24/7 access to the content, meaning they can do the work to earn the credits whenever they like

> much easier to go to a single source than find CPD credit content elsewhere

> unique content inside (think Netflix Series vs cable TV, you only get it here...if that's true)

Your advertising campaign needs to be funded by a % of revenue after the launch, and be relentlessly continued.

Getting lists of GPs should be very easy.

Also advertise to existing customers, to remind them of why they're a member.

Happy to discuss sales & marketing ideas on a call.