I started it at home after a hospital visit, my O2's weren't up enough when I left, but I was eventually able to be off during the day, then another hospital visit, then finally my lobectomy 3 weeks ago, I didn't need it like Lindsey, but I can tell now when I need it. I did an overnight test about a year ago and didn't need it at night so it wasn't until the hospital visit in Aug. that it changed.
You can always ask for the test overnight, best thing to do is get your own oximeter, which sadly insurance won't pay for or if they do they pay for half which home health companies jack up the price to double anyways that it's better to just buy online. A good brand is Nonin we just bought off their website I think.