Heath Care or Healthcare?
There are now several de facto standards that are mostly agreed upon by online communicators.
health care or healthcare?
answer: health care, two words all the time.
The current acceptance now is 2 words, in all applications.
At one time, the usage rule was "healthcare" if it was used as an adjective, and "health care" if it was used as a noun.
The verdict is in: "health care" in all applications for much the same logic that we don't use "medicalcare" or "nursinghomes." *
theatre or theater?
answer: depends on usage.
Lou Bellamy, founder and artistic director of the Penumbra Theatre in St. Paul considered the spelling of theatre when he named the Penumbra. "It's my feeling that R-E connotes the 'craft' and that E-R connotes the building within which the craft takes place." **
Locally, the Guthrie, Jungle, Fitzgerald and Varsity fall in the E-R camp. Penumbra, Mixed Blood, and the State/Orpheum/Pantages (the Hennepin Trust properties) opt for R-E.
Normandale's theatre program agrees with Mr. Bellamy, so follow that rule: E-R = building, R-E = craft.
The Mobile Influence:
one, two, three, four, five, six, seven, eight, nine, 10?
Here's a rule that is changing over to all arabic numbers in all cases and situations online because of readability issues with small (mobile) devices.
Users will IGNORE text numbers when scanning text on a web page. They are less likely to ignore arabic numbers, so use those always.
answer: H1, H2, H3 OK.
Most authoritative sources haven't caught up to the current reality of the online experience, which is rapidly becoming the mobile experience.
A very good and complete online style guide is at Hunter College. On that, they inveigh against deploying all cap headings on web pages: "Avoid writing in all capitals on the web, especially in headings and page titles." Yet their navigation menu items are in all caps. And those are in all caps because any web designer knows they are easier to read in that format on small screens.
Our heading 1, 2 & 3 formats for page headings are styled as all caps for easy legibility in all sizes of displays.