Define “IR”. Proper night vision uses an image intensifier (the sparkly, grainy image you see in the movies... though it’s less grainy and a blue white colour now), these amplify a wide range of colours from green to into the near infrared. They’ll blow your socks off with what they’ll show outdoors even under heavy tree cover, with no moon away from towns. Most are monocular, there are binocular options, the lower cost models have one intensifier and split the output into two eyepieces... “doing it properly” uses two monoculars bolted together. If one unit is horribly costly, then you can imagine the cost of two... however the contrast boost is impressive (just like using binoculars vs a scope).
If you want to go wildlife watching at night with old fashioned glass binoculars I hope you’ve been eating plenty of carrots as you won’t see a whole lot!
Digital night vision is cheaper, but doesn’t work well when it’s really dark without an “illuminator”... very bright light that’s far enough into the infrared that the camera wi I’ll see it, but you hope the wildlife doesn’t!
If you like looking for warm beasties at night then intensifiers/digital night vision provide no colour information and if stuff isn’t moving about it can be real hard to pick stuff out... however, unless it’s cold blooded it will be warm and so thermal (long wavelength infrared) cameras will show it up nicely... makes it very easy to spot stuff. Thermal isn’t cheap either, but it is more widely available and stuff that’s actually useful is now far more affordable than it was. You can get thermal binoculars, but then they do the same 2eyes from a single detector, so not a true binocular.
Spy.... the right stuff allows you to move about quietly at night without the need for lights, so unless people have similar kit they’ll not know you’re about.
PEter