I do not have a serious deer issue. They come once in a while but the damage is minimal.
My problem is with woodchucks! For three years I had one. For the last year it has been two chuckers!!!! I will recommend Tractor Supply to you all. I purchased a product that deterred woodchucks, squirrels and rabbits. It has to be reapplied weekly, unless it rains. Then you reapply after the rain. The spray lasts about a week and is pretty effective. It has eliminated about 90% of the munching!! Nothing will be a guaranteed 100% effective. That ain't happening.
But Tractor Supply is largely about farm animals, rabbit as a pet care, cats, dogs and controlling the eaters as much as possible.
They have the motion sensors. You point the sprinklers at the plants that you want to save. Not anywhere else!
I use my backyard security light. I have it on some nights, off on others. The pattern is random. Walk outside once in a while after it's dark. Let the neighborhood see you, let the animals see you, be unpredictable! By breaking your routine you just may make those critters go somewhere else to eat.
The last thing you want a doe or a buck to realize is that there is a pattern. Come on, you are smarter then they are! Come on my fellow humans!! Get aggressive, get unpredictable, be spontaneous.