Disposable diapers; please share your experience.

How can you tell if the adult diaper is wet?
Some have a wetness indicator.

DUAL WETNESS INDICATOR turns from yellow to blue when moisture is present, making it easy to know when a change is needed. Ultimately, eliminating unnecessary changes and overall costs.

You asked if using the incontinence product will "make him lazy and perhaps not even use bathroom"

In my experience people don't wet/soil themselves unless they are either physically or cognitively unable to do otherwise, we've been conditioned from early childhood to regard that as taboo.

In addition to what the others said , You could also try to get him to go to the bathroom every couple of hours . So he stays dry , and has less leaks and you use less disposable underwear

You may have to do what I did with my late husband and that is throw away all of his old underwear and replace them with the men's Depends, and just call them his new underwear.
When he has no other option but the Depends, he will come around to wearing them.
And you may have to follow him into the bathroom to see if in fact he needs to put on a new pair of Depends underwear.
Best wishes.

How often to change is going to depend on how much and how often they are used, I know that because they are a new expense many thrifty people tend to leave it too long and then experience leaks and odour. Just like children's diapers modern products wick away moisture so they won't necessarily feel wet and uncomfortable, but you can usually tell by the weight when they are getting full. Men's guards might be sufficient for occasional leaks and dribbles.