I recently "fixed" a Wordpress site for a client. He told me the site's host had "malware problems" and he needed the site restored from a backup. I did that, and didn't change anything else about the site. I noticed many plugins and Wordpress itself were pretty out of date but this is typical for this guy and he did say it was the host's fault...
Fast forward a week and now he forwards me a message from the host, presumably very much like the first one he got earlier (which he neglected to send me then), which explains his site was infected again through a vulnerable plugin. The email lists the file and line number that contains the exploit. This was frustrating to me because I have better (and better-paying - he's an old client on a "legacy" rate) things to do than deal with this guy's failure to communicate/understand the problems he creates for himself, again.
I would like to make this situation better for both of us by changing the nature of our relationship (at least for this site if not more) from hourly on-demand work to a monthly fee where I spend some time on a regular basis to prevent these kinds of problems before they happen by keeping things up to date, changing passwords, etc. This would ensure I get paid more regularly (and I can keep myself from wasting more hours by working intelligently to start with, rather than fixing stuff for him after he breaks it), and it would ensure his site doesn't keep getting screwed due to negligence/ignorance.
I am not sure how to bring this up however, and I feel like it's hard for him to take me seriously as a potential service (compared to a developer-on-demand like he sees me now). I said once already in an email that he needs to keep things up to date or problems will continue, and I could take care of that if he wanted. He did not acknowledge this statement but instead focused on the problem at hand and just asked how long it will take to fix. I am trying to come up with a more compelling way of explaining I no longer want to waste both of our time doing this hourly work fixing problems that should never exist in the first place if he had me handling things on an ongoing basis. I am asking for advice and examples of this kind of transition communication-wise.