Healthy depends very much on the relationship, as a sibling post pointed out. I'm not a fan of the "if you have nothing to hide" argument in the general case, but in this case of my wife we have nothing private between us. In fact, its the things we share that make up the bulk of what I consider private from others. I figure that if Google, my cell provider, the government, and who knows how many other corporate entities have ready access to my location data, why not her? In practice she has more interesting and useful things to do with her time than watch me all day.

We have it on all the time, but for us it's because we moved out to BFE and don't know our way around very well. It's very possible for us to be lost and damned.

Healthy is as healthy does. Our relationship kicks ass, so "location on" isn't a trust issue to us, it's an "oh dear, hopefully my loved one wasn't kidnapped" issue.