USB testers are cheaper now, I'd advise anyone to buy one preemptively.
It's nice to one-off check a new cable to know what it can be used for, with the additional benefit of seeing the power curves for the higher models (e.g. see a charger's power output drastically drop down as it overheats)
I'm using a super cheap Ali-express one I checked against well know and stable brands of cable/chargers (e.g. Apple and Anker's power bricks and cables).
Otherwise AVHzY is I think the recommended brand, with two levels or pricing depending if you want external output.
It's nice to one-off check a new cable to know what it can be used for, with the additional benefit of seeing the power curves for the higher models (e.g. see a charger's power output drastically drop down as it overheats)