This is most often done for desserts like Crepes Suzette, but also for meat dishes like coq au vin, for example. I use it in some of my recipes to enhance flavors.
If you decide to do it, make sure you are very careful. Take the meat off the stove away from an open flame. Make sure there is no overhang to avoid fire. Use a long match or long lighter. The liquor needs to be warmed before flambéing. You have to light it very rapidly after the liquor has been added.
It is an optional technique in my recipes. Should you want to use it, be very careful and follow instructions in the links below.