Have you hired a web site developer who built your site, provided support for maybe a year, and then said they couldn’t continue to do so?
Unfortunately, that’s not THAT uncommon of a story, and it’s why you should look at how long a company has been developing, maintaining and supporting web sites. Initial build and release is important, but so is the help that comes in this evolving environment.
ESPECIALLY if you use WordPress.
A good question to ask your designer is what they expect they will need to do for the site after one year. They should be able to answer that SOMEBODY has to do things such as software updates and support, theme updates, security monitoring, and helping the client with changes they can’t quite figure out for themselves. There should be an annual cost for this. If there isn’t, then they aren’t making a regular process of providing that to their WordPress clients. It should already be part of the first year cost and easy enough to pull out. There’s no guarantee the amount will remain the same in the following year – projected workload could change, plugin software or the theme may need tweaked or replaced over time, security monitoring can (and probably will) increase.
If you can’t get an estimate, that’s a red flag that they haven’t planned on offering it. Ask for it, and listen to the answer carefully.