If you're unsure whether or not your Baileys has gone bad, there are a few things you can look for. First, check the expiration date on the bottle. If it's expired, it's probably best to discard it. Next, take a look at the appearance of the liquor. If it's significantly darker than when you purchased it, or if there are any lumps floating in it, those are signs that it's gone bad. Finally, give it a smell. If it doesn't smell like Baileys anymore, or if the odor is particularly unpleasant, those are also indications that the liquor has spoiled and should be thrown out.