Just have a quick question regarding Liquor and shelf lives. I was cleaning out my refrigerator today and came across a half full bottle of vodka that has been in there for gotta be almost 3 years by now.

Do liquors ever expire? Also have a quarter full bottle of bourbon that's been sitting on my computer desk for god knows how long (4 years maybe more)

Not talking about liqueurs that often have additves, just straight liquor. Will probably just try them out of curiosity.