Most businesses don't need an in-house developer on staff just to keep a website secure and current, which is why our maintenance plans cover uptime monitoring, CMS core and plugin updates, security patching, and routine backups on a defined schedule rather than an ad-hoc "call us if something breaks" arrangement.
Plans typically pick up where the initial post-launch warranty ends, and include a defined response-time tier for issues along with an allotment of minor content changes each month, so the site keeps working the way it did on launch day instead of quietly degrading as plugins and dependencies age.