A tracker in your checked bag tells you where your bag is when the airline doesn't. If you have an iPhone, get an AirTag. On Android, get a tracker that works with Google's Find Hub. All of them are allowed in checked bags.
iPhone: the AirTag, and why airlines like it
The AirTag (2nd generation) is the easy pick for iPhone users. Apple says Precision Finding works up to 50% farther than the original and the speaker is about 50% louder, which helps in a pile of identical black suitcases. The battery lasts about a year and you can swap it yourself.
The real reason it's worth it: Air Canada, WestJet and Porter all accept Apple's "Share Item Location". When your bag doesn't show up, you send the airline a link to your AirTag's location along with your delayed-bag report.
Android, or a mixed family
The Chipolo POP works on either Apple's Find My or Google's Find Hub (one at a time), so it suits an Android phone or an iPhone. It has a replaceable coin battery and a loud ring, around 120 dB. On a Samsung Galaxy, the Galaxy SmartTag2 uses Samsung's own finding network instead; it's not for iPhone.
Put it inside, not on the outside
A tracker clipped to the handle is easy to pull off. Put it inside the bag, ideally in a zip pocket or a tracker holder that stops it rattling against the shell.
If your bag doesn't arrive
Check the app at the carousel first; you'll know if it's still at your connection airport. File the delayed-bag report at the airline counter before you leave, keep the file number, and share the tracker's location with it. Keep receipts for essentials: on flights to or from Canada, the Montreal Convention and the airline's own rules decide what you're owed.
And no, the battery isn't a problem in the hold. ICAO lets devices with less than 0.3 g of lithium metal stay switched on, and a coin-cell tracker is well under that.