Website maintenance is four things: keeping the software current, keeping the backups real, keeping an eye on what silently breaks, and confirming the site still does its job. Almost every small business site failure traces back to one of those being nobody's responsibility.
The list below is genuinely usable. Work down it and you will find something, and the something is most often the contact form. Nothing here requires a specialist except the parts we have marked as such, and where a task is easy to do yourself, we say so rather than pretending otherwise.
If you would rather it was somebody else's job, that is what maintenance and care plans are for. If not, the list still works.