I have researched this on the forum but am still unclear about on several points. I hope someone can provide some brief guidance.

example: small network with 50 permanent clients using CPEs and one hotspot; accounts managed with Mikrotik usermanager.

I understand there might be advantages to handling the two types of clients differently; PPPoE for the CPE clients and Hotspot for the 'hotspot'. Is this correct?

The hotspot users can sign-up, pay and manage their accounts on their own while the CPE users would require account setup when the equipment was obtained. Once set up, it would seem that PPPoE users could log in to the usermanager and make payments as long as the account has time and is authenticated.

My main question is: if the 'paid for time expires' on a PPPoE account and the client wants to add more, is there a simple way to allow the client to handle this themself - when the account is not being authenticated or must the client call in and have support staff do this?

I had considered using Hotspot and PPPoE on the same interface and while I did find several posts of people doing this it seems that the practice is recommended against. I had imagined the Hotspot would catch the 'failed to authenticate PPPoE accounts with their CPE default IPs and allow them to pay - after which the CPE would automatically log in again on the now authenticating PPPoE account. Even if it it worked the solution seemed convoluted and cumbersome and wondered if I have overlooked something simple since I don't have anyone else here to discuss things with.

What is the best system which allows PPPoE users to pay automatically?

thanks