Is a shoe insert or watch a better device for wandering?

Does this person (not sure if you are asking for your husband or your ex) have a cell phone?
A cell phone also has the capability to be tracked and if this person does not leave without the phone that is great.
If they always have keys on them you can put a tracker on the key ring.
There are no fool proof 100% reliable tracking devices because we are dealing with humans.
they can leave without shoes
they can leave without a watch
they can leave without keys
they can leave without a cell phone.
The only way is to keep them within your vision. Trust me I KNOW all to well that is impossible. I wore my house keys around my neck for 5 years. I NEVER took them off. My Husband STILL managed to "escape" 3 times.
If it becomes a danger then you might really have to consider placement in Memory Care. (even then there have bee reports that residents have managed to escape)

I think that depends on whether they are more apt to wear the watch or the shoes. Nothing is foolproof, people have been known to leave the house in slippers or barefoot, people can reject a watch (especially if it is big or "ugly") or to take it off at night and leave without it.

tshoug, instead of those items, if your hubby tend to wander at night, put down a black throw rug in front of the exit doors at night only. Since hubby has Alzheimer's/dementia, he may think there is a large hole in front of those doors. Hope that works.

The best way to keep a "wanderer" safe is to have a safe environment and to have a person who is watching him/her. Memory care units are usually locked so that their charges can not wander off the premises. These facilities also tend to disguise doors as walls or bookcases to keep wanderers from lingering at the doors in wait of an opportunity to escape.

My mother constantly fidgets with her watch, rings, necklaces, etc., so it's impossible to keep any type of tracking device on her. So instead we've installed an additional lock on the top of every door (the sliding bolt kind) and we have an alarmed mat next to the bed so we know when my mom gets up. Even if mom avoids the mat when she gets up (which has happened on occasion!), there's no way she can get out of the house.

The main thing is it needs to be something they won’t remove. We put one on shoes, and she never noticed. We also had one in her coat pocket because she never left the house without her coat.

I've tried several options, including different watches and a shoe device. None of these worked well either because my husband took them off or the GPS system was inadequate. I finally found something that works really well called a jiobit (see jiobit.com). It's a small device that can be attached to clothing, belts loops, etc. It has an excellent tracking system that is pretty precise. You can even set up a family and friends support network so that others can help you track your love one.
My first line of defense is a door chime system (secrui) which was easy to install and has been very effective. Plus, I have a special lock on the main door. All systems are subject to human error. I have on one occasion failed to replace batteries in the door alarm system in a timely manner, forgotten to lock the door, and neglected to attach the jiobit. As a result, my husband wandered away, but thankfully didn't get far.

In my mother's memory care facility they have alarms that go off if a resident gets close to the door. I think they work in conjunction with the ankle or wrist bracelet. My mother tried to cut off the ankle bracelet. That's when they took away all sharp objects in her apartment.

Another thought on this.
I heard one case where the spouse / caregiver placed different door knobs on the door and just the extra door knobs was enough to confuse the person trying to open the door.

Whole wondering is a fear, there are drawbacks to both. Shoes are not worn all the time so I would probably suggest not going with that option. As far as a watch style as long as the patient is used to wearing something on their wrist and leave it on, it will hopefully keep the loved one to be able to be found easier should it have GPS capability. The problem is by the time you know the family member has wondered, any number of things can happen. It is IMHO best to have safeguards in addition to the watch style unit. Things such as window and door alarms, make sure they are ones that are loud enough to hear through your home if that is were you are planning on keeping your loved one. Dementia care/living centers are set up to prevent their wondering. Gardens have no ability for them to wonder, but allows them to get fresh air.
Good luck