First of, Craft is very different from WordPress. With WordPress you can build a site without writing a single line of code using prebuilt themes and plugins, so it's easier to answer questions like Can updates break my site? With Craft, the frontend is built from the ground up by the developer, so the differences between Craft sites are much greater (by default). So many of your questions depend on how your developer has created the site. Figuring that out should be the first step anyone should take before touching your site (no matter if it's you or someone you hire).
Am investigating migrating to new host as we are currently paying far too much for a dedicated server which is unnecessary for a local business networking website.
Careful here: Current versions of Craft CMS aren't really meant to run on shared hosting (the kind where you upload a ZIP using FTP and everything just works). What I'd recommend is a VPS (virtual private server) controlled by a server management tool (at work, we use Laravel Forge). Good VPS providers include Digital Ocean or Hetzner, for example.
A solid VPS for a small to medium traffic site will cost you maybe 10~15€ / month, and the basic Forge subscription is 19$ / month.
Do Craft updates need to be installed promptly?
Not necessarily, though I would keep an eye out for security-related fixes. Those should be installed quickly. But it's rare for a serious vulnerability to make it into the core. Make sure to check the changelog every once in a while.
Can these happen automatically via the host or manual only?
Depends on the setup. You can configure the site to allow updates in production, but that is heavily discouraged. The recommended workflow for updates is to install and test them in a local development environment first. Once you have verified everything still works correctly, commit the updates to git (dependency versions are tracked in your
config/project/project.yaml files). Then deploy the changes in production (this is the step you can automate with a tool like Laravel Forge).
See Deployment Best Practices for more details.
That said, if the site is a bit older and wasn't set up using a proper deployment workflow, none of this applies – in this case, the first thing I would do is get the site under version control and set up a proper deployment pipeline.
If manually are these updates best done by an expert? I have read posts where users have problems.
Yes. Because the frontend is built manually by a developer, Craft updates might break something in unexpected ways. Also, following the deployment workflows mentioned above requires some knowledge in how to set up a local development environment, use tools like Composer and git, and how to fix things if something breaks.
Might updates break the website which I'd then need to get fixed?
In general, minor and bugfix versions (see Semantic Versioning) shouldn't break backwards compatibility, so in theory only major updates should require manual adjustments (so every update that increments the first number in the version, from 3.x.x to 4.x.x). In practice however, you might run into edge-cases where you still need to adjust something. For example, if some code in a template depends on undocumented or buggy behaviour which gets fixed in an update, the template might not work as intended anymore.
If the Craft license key is migrated with the site, that means we just have to keep up with the annual ongoing license fee? Would it be easy for me to go into the backend and change any licence details?
Craft license keys are tied to a single domain and a Craft ID account. Make sure to get the login details for the Craft ID account used for your license, or you might have to contact Pixel & Tonic to get the license reassigned manually. See these links for more information:
Typekit fontface is registered to the developer (think that's no longer legal).
Will that be easy for me to nip into the backend and either change that licence info and/or font (could go googlefont similar for free?). I won't have access to the backend til the site is migrated.
It depends on whether the site is under version control (see above). But it also depends on how the developer included the Typekit assets and how the site is built in general. For example, if the CSS for the site is compiled using something like SASS, you might not be able to change that on the production server at all. In any case, you really want to get access to (or set up) the git repository for this site and make sure to follow the proper procedure for changes like this – in this case, change the font locally, (recompile if applicable) and check the site, then commit the changes to version control.
Finally difficult question ... do I start learning Craft and php at the age of 60 when I still appreciate a social life and full night's sleep (have history of html, css, started php but never completed) ... or is a moderate level of knowledge easily achievable.
I'm only in my twenties, so I can't tell you that :)
But in my opinion, you're never too old to learn!
One thing that's a bit annoying about the current development landscape is that you have to get familiar with a lot of tools before you can properly work on something. Even a simple change like the migration from Typekit to Google Fonts might require knowledge of git, SASS, maybe Webpack, Composer, and more …
That said, the first thing I'd do is figure out how to set up a copy of your site in a local development environment and get comfortable with the basics of git so you can try changes without worrying about breaking anything in production.