As a consultant for WordPress web hosting I will always recommend keeping your site as up to date as possible as falling behind can cause the site and worse, my host to be hacked by known problems, unnecessary problems.
But the update to WordPress version 5 has been a hot topic as it changes to a new editor, and change is scary. Personally I like the new editor, it uses blocks for all its elements and (theoretically) requires less knowledge of HTML. But it is different and is a change.
I ‘manage’ all the sites I host for others that is I do the updating and I have chosen to go ahead with version 5 but am keeping the old editor in all the sites.
If I am your host and you would rather use the new Gutenberg editor you need only activate its plugin from your Admin Plugin page. Or if you prefer, contact me and I’ll activate it for you and help you through understanding how to use it.