Although this is largely up to you to determine, there are two exceptions.
First, if a site generates revenue of any kind, in any amount, it cannot be a non-production site.
Second, the number of non-production sites you can have is limited to half of your sites, rounded up. If you have more than one site, some of them must be production (or critical) sites regardless of what they're used for. If you have too many non-production sites, our system will apply an Excess Non-Production Sites charge to make up the difference.
Beyond those two criteria, it's your decision. If you have a gut instinct that one of the options is best, you're probably right. If you're not sure, look at the restrictions associated with non-production sites, and the additional custom monitoring associated with critical sites. If your top priority is low cost and you can live with the restrictions, your site is probably non-production. If your top priority is stability, your site is probably production. If your top priority is availability at all costs, your site is probably critical.
Sites that people tend to regard as non-production include (but aren't limited to):
- Personal blogs and home pages (that don't generate ad revenue)
- Personal resume and portfolio sites for people who change jobs every few years
- Experiments and "I want to see if I can set up X" sites
- Beta/development versions of another (production) site
- Future production sites that are under development and not yet available to the public
Sites that people tend to regard as production include (but aren't limited to):
- Most public-facing business, club, and organization sites, whether or not they generate revenue
- Blogs that show ads or otherwise generate revenue
- Resume & portfolio sites for contractors, consultants, gig workers, and other people who expect frequent traffic that leads to paid work
- Active forums with many participants
Sites that people tend to regard as critical include (but aren't limited to):
- Any site that generates more than about US$100 per month in revenue
- Business sites where business operations depend in any way on the availability of the site
But, to reiterate, as long as you maintain appropriate ratios and follow the revenue rule — that non-production sites may not generate revenue — the choice is yours.