What’s your strict regime?
In no particular order...
Boots are only worn for hunting; never in a vehicle, gas station, etc. If I need to cross a road, I'm careful where I step. There are all kinds of odorous substances spilled on roads.
Never handle boots with bare hands.
Always remember that fingerprints equal odor. Handling boots with bare hands every time you put them on/off leaves a build-up of skin oil (odor) and that odor will transfer to anything the boots touch in route to your stand.
Boots
always go on a boot dryer
every night. No exceptions. All boots, rubber or leather, will have some level of moisture inside after a few hours of wear. Moisture produces bacteria which produces odor. Keep the inside of boots as dry as possible.
I treat my rubber boots with ozone daily. Yeah I know...ozone is supposed to be hard on rubber but I run a short 5 minute cycle each morning while I'm showering so they are fresh and ready to go each day. I do believe ozone destroys rubber if exposed for extended periods. But I've not had any issues if the treatment is short and then aired-out asap after the treatment. Ozone kills odors that it's exposed to quickly, there's no need to treat boots for long periods, and never store boots in an O2 environment (tubs, lockers, closets, etc).
I store boots with sachets of granular carbon inside them.
I use a bee smoker on my gear. Smoke is not (just) a cover scent, smoke inhibits bacterial growth that's why smoke is effective in preserving food.
I don't place my boots in a closed tub after the hunt until they've been dried.
At least once per year, rubber boots get a thorough washing inside and out.
I can't say which of these practices are more effective than any of the others on the list. But what I can say is I never have busts from ground odor. Some deer will smell ground disturbance but there is no negative reaction, it's more curiosity than anything.
I hunt small properties with extremely limited access routes. There is no way that I can access many of my stands without walking across, on on deer trails. Odor free boots are mandatory if I hope to keep stands fresh and not burned-out. But there's another aspect to getting in and out of stand locations and that is to do your very best to not touch anything if you can avoid it. I always carry hand pruners and I prune paths (private land) or use them to push stuff out of the way. I'm not concerned with touching anything until I'm in my final approach to the stand, or when I'm in other "sensitive" spots like scrapes, rub lines, bedding, etc.