I've done maybe 5 or 6 same-day ex-EUs (non-b2b) but my attitude to risk is becoming less cavalier each time, i.e. I think I'll more than likely stick to b2bs and overnights in future. Thankfully, many of the cheaper starting points (for my typical trips, at least) are wonderful cities to spend a day in beforehand. Specifically
this tale of woe in the QR forum made me very nervous about my same-day ex-CPH QR trip a couple of weeks ago!
On the way home, I typically book same day, latest flight home but with SDC flexibility to move forward if feasible.
SDC is only possible on Avios tickets and if you have status, right?
I have no status - chasing Silver with this QR fare, so I’ll book my positioning flight with BA to get in 2 of the 4 required sectors.