>>We have never tested for it, (why waste materials when it adds no data, or help, and you are already self-quarantined by then?)

Agreed if you're already self-quarantined BUT it is (or at least was with previous variants) possible to be infected and infectious and not know it, at least for a day (maybe longer - I'm not sure what to make of people who've been infected w/o symptoms - were they infectious some of that time?). The point of testing is to make sure you're not about to give the bug to someone else even though you don't feel sick then.

We have a close family friend who's in her 90s. We tested before visiting her, just visit by phone if either of us feels at all unwell.

It's possible that Omicron doesn't have an asymptomatic phase, so your comment about waste of materials could be correct now.