When do people with Alzheimer's usually start to wander?

There isn't any rule about this and some people never do wander. How far away do you work, could you actually get to him if you watched him go out the door or saw him do something else dangerous like start a cooking fire or climb up on a chair to change a light bulb or _______? Having eyes on somebody is not a substitute for supervision, in my opinion it gives a false sense of security.

Two thoughts:

Get him a wearable gps unit - check the ALZ store or your local police detachment may have this service available (in any case it wouldn't be a bad idea to inform the police that someone with ALZ is living at your address).

Consider adult day care - this will give him a social outlet and you peace of mind.

The first thing my father experienced was getting lost when he drove to the store, I had to figure out where he was by asking him what he could see and then go there and have him follow me home, he did this again when he went for a walk. He had walked five miles and became confused, fortunately a local policeman helped him get home. When all this happened he was much like your father, still functioning fairly well but easily confused. My recommendation is to check with your local police and find out if they offer a free location tracking device that your father wears like a wristwatch. This is tuned to a specific radio frequency that they can track even through buildings. If your area doesn’t offer this there are various ones in the market for a fee, it can connect to your phone so you can see where he is at. These vary greatly in ability so if you go this route I would spend the extra if you can afford it and get the best one possible, ie one that can even track him if he goes inside somewhere. My dad is in stage5-6 of Alzheimer’s and I have put padlocks on all the gates so he can’t take off on me, before that I put a driveway alert at the end of the driveway so I would know if he was headed out to the road.

Is finding the bathroom when he has just woken up the only problem? Some people would put a line of tape on the floor to help him find the way. It's easy to be dozy when you are half asleep (especially with meds), but perhaps you gave it as an example and there are other things that you are noticing as well.

My mum was a wanderer before her official diagnosis two years ago. When she moved in with me, again 2 years ago, I bought a GPS tracker which I put in her handbag. I told her that it would send me a message if her handbag got stolen/lost. She accepted that.
I could track where she was online.
Now she doesn't wander, but only because she cannot go out on her own anymore, due to her dizziness and falls. She's accompanied by me, my husband, or private carers.
But if she could, she would probably still go out and get lost!

My mom is 6 years in and she has yet to wander. She does think she has somewhere to be and is determined to get out the door. My heart goes out to you as you enter this journey.

I don't think all Alzheimer's patient's do wander first of all. It doesn't sound like he tends to go places on his own and if that's fine with him he might not be as driven to wander away from home. You also don't have to worry so much about him getting lost that way. But there are inexpensive security camera's available, I got a couple on Amazon for my Mom's that trigger when there is activity. We have one overlooking her garage/parking area so we can see when people arrive, in particular the ADA Van that takes her to pool and therapy appointments but you could use something like that at the door or each door he might use if that's a worry. We have talked about getting a door bell with that feature too we just haven't done that. We also have one over her bedside/couch table (large table) that shows the area where she keeps her medication (set up for the week) and appointment book which she uses to write her BS and wt each morning. We check that camera each morning and evening now to make sure she has taken her meds by a certain time because the new heart meds are time specific. Both cameras will always show us what's going on Live, the garage camera alerts us when it's triggered by movement and stores a certain number of those, the inside camera saves a clip every time it is triggered by movement for 24 hrs I think it is so we can go back and check event's which has come in handy more often recently. The inside camera I have mixed feeling's about it kind of feels like invading her privacy or spying on her but she does know about it and it saves my brother, who lives closest, from having to drive the 20-30 min to check on things when things get off, it helps us keep things from going way off the rails and at this point it is keeping her independent and in her home a bit longer so the trade off works. We (my brothers and I are the only ones with access) all feel uneasy about it too so only use it when necessary. We also have 2 Echo Show's but you probably don't need to think about that since your father lives with you. The camera's though while not perfect would pretty good for alerting you when he leaves the house and comes back or even enable you to see that he is staying in the yard if that's helpful depending on the view you set. We have fairly inexpensive ones (the outside camera is the lowest quality) and they work just fine for our needs but we do have to put up with constant alerts when it's windy for instance or when it's raining buckets and sheets of rain are blowing in a certain direction. The sensitivity can be set though and you could turn alerts off when your home but I think the better cameras probably deal with some of those false alerts better. The camera's do give us so much more piece of mind and without them I think we would be in a very different place so the little annoyances are well worth it. On the other hand maybe he wont be a wanderer at all! Good luck.

For me he is already wandering, but in his home, so dont worry too much he still finds his way inside, the problem will be serious if he does not find the toiles. The moment he starts wandering outside the house and does not recognise the serroudings and feels lost. Noboddy can say precisely when either of both situation will take place.
Be attentive for the moment. He start to be in an other reality and does incohérent things which he never did in the past.
Then he really might start wandering incoherently i.e he might dress and take an umbrella and go outside etc. If at that moment you were ther and could ask him what he is doing, he would probably tell you something that is not cohérent.
A newproblem for you will start…

You may want to check with your local office on aging, police department or county resources. In Prince William County, VA, where my dad lives, they have a free program where the sheriff's office can place a GPS tracking device bracelet on those with memory or developmental issues. The GPS can track within 5 miles of his home if ever needed. They also have the phone numbers of family in case there is an issue. The sheriff comes to his home and replaces the battery every 60 days. We told my dad is was his "Dick Tracy" watch (from the 1940's). So far he hasn't wandered but it gives us peace of mind in case he ever did.

https://www.alz.org/help-support/caregiving/stages-behaviors/wandering

So far, my mother has not wandered or even had the inclination to do so. She complains of being dizzy all the time so hopefully she will not become a wanderer. I LOVE the idea of placing cameras in her home to keep an eye on her when I cannot be over there. Like your father, she is living in her own home and we hope to keep it that way for as long as possible. Cameras are a fabulous idea! Wishing the best for you and your father! Blessings.