Sounds goofy... i would assume its either:
if its the latter and/or you norm dont think along those lines... SP Geoff actually wrote a cool book in the 2013 days i would consider the 'large enterprise SP services contract guide'. obv the svc apps and dev tracks are a bit diff but still holds up conceptually: https://www.amazon.com/Microsoft-SharePoint-Planning-Adoption-Governance/dp/0735671648
So there isn’t really a cookie cutter deployment, save some best practices... and provisioning (below the web app level), information architecture, operational service offerings and governance will depend on your org/biz usage needs.
Small company or large? Who owns the farm? Will separate resource assist customers then farm admins? Who owns the site? Who supports what? Will site collection admin be handed out? What SLA like reach back or support services will be entertained/supported? User training, dev standards, marketing, support service portal/communications conduit planned out?
Somewhat cliche but you really need a strong partnership with or champion in informational management and business executives. If not you'll always be a tool looking for an audience and being used incorrectly (hammer jar opener/file share/bad relational database woes go here).
Note, I'm not Geoff and get no profit from you buying, but his book is amazing: https://www.amazon.com/Microsoft-SharePoint-Planning-Adoption-Governance/dp/0735671648/ TL;DR how to support and structure SP services in an org. Even if you are a 2 man shop, skim it take away at least 5% of the content/concepts and you'll be golden'ish.
Would search through other posts here for more long winded answers from myself and others... but, many vs few site collections comes back to my aforementioned ownership questions (shared assets/dev effects go here) and capabilities of users (i.e. site collections are significant boundaries to power user dev/info sharing, IMO).
Good luck!
Oh, and careful on terms, not nitpicking but assuming you meant separate site collection*. Ie subsites/webs belong in site collections, site collections organize sites in the farm. In the ui sites are webs. Via PowerShell Sites are Site Collections, Sites/Subsites are webs... not at all confusing :). Welcome to SharePoint!
SharePoint devs generally dont know poop about architecting or admin'ing :/
http://www.amazon.com/Microsoft-SharePoint-Planning-Adoption-Governance/dp/0735671648
For a pretty comprehensive critical overview. Grab an admin book on the how.