My left eye is always red requiring OTC eye drops. Should I use OTC eye drops? If not what should I use?

Have an exam. Have an eye md evaluate you. Chronic red eye(s) can be due to many things and an eye exam can help to sort out the cause(s) of your red eye. Otc drops that get the red out will only mask the symptoms. Chronic use of these types of meds may actually result in rebound redness. Use artificial tear drops. They are the safest but don't necessarily make your eyes appear whiter.
Red eyes. Red eyes could be due to allergies, dry eyes, or eye infections. The treatments are very different. For allergies, zaditor (ketotifen) is a good otc eye medicine. Naphcon-a can help reduce the redness. For dry eyes, lubricating tears are necessary. For infection, usually of the eyelids, start with eyelid warm compress and diluted baby shampoo scrubs. You should have a baseline exam with your eye doctor.