Since they require a battery, these of course can die, rendering the scope useless.
We compensate for that fact by simply doing 2 things.
Always check your scope before you leave your house!
We also tape a spare battery and a dime under the stock of our crossbow.
If you use camouflage duct tape, no one can even see the battery hidden on your crossbow, and all it takes is the dime in order to open the scope and replace the battery.
Parker Red Hot Illuminated
Another type of crossbow scope is a magnified scope.
These crossbow scopes make the target appear bigger and closer, which is a tremendous help if you have poor eyesight.
My fiance was having trouble seeing through her scope without her reading glasses.
I put the 3x Pro-View on her TenPoint Pro Slider and she could see great without the glasses and happened to shoot a dandy buck on her first night of using it!
Many of them also have light gathering capabilities.
This is extremely useful, if you are hunting under certain situations,
such as in a blind,
which makes everything appear darker than it is.
These scopes have crosshairs or multiple lines that are sighted in for various distances, usually in 10 yard increments.
TenPoint 3x Pro-View
Some of them also come with red and green lighted dots, in the center of the crosshairs, to illuminate your shot placement.
I, myself, prefer the TenPoint 3x Pro-View Scope on my Defender.
It has multi-lines for different distances and you can also turn on either red or green dots depending on the light conditions.
It also has a zoom-focus on it, which is very helpful to us who no longer see as good as we used to.
I found this scope to be extremely helpful in getting the last few minutes of hunting time in while hunting from a blind.