With three clients it is still manageable. With fifteen, maintenance eats time nobody pays for.
Each is work that is not in the contract and cannot be invoiced.
A plugin update took the client's site down. You sit down to it in the evening, because they have an investor meeting tomorrow.
In LessCMS: there are no plugins to update and no server to watch over. An outage on your side has nothing to grow from.
Certificates, backups, PHP versions. A working day spent checking that nothing has fallen over.
In LessCMS: certificates and backups run themselves. The review is a glance at the project list.
You have to add hosting and maintenance, which makes you dearer than the person who does not count it.
In LessCMS: maintenance sits in the client's subscription. You quote for your work, not for someone else's servers.
Projects sit side by side and you switch between them in one click.
The header and footer you like move between projects.
They pay for their project and you keep administrator access.
Create a free account. You do not have to move everything at once.