Depends on what you're doing. If you're doing bodybuilding, you have to train your arms I think. Bodybuilders have disproportionately large arms IMO. OTOH, if you're doing powerlifting, I don't think you have to train your arms directly, you'll get tons of indirect work from your compound lifts and accessory work, and your arms will be strong enough to do everything you need them to do.
That said, I've heard of a few programs that have people squatting every day. Stronglifts for instance, albeit only 3 days per week. John Broz has his lifters squatting 5 days a week though. I think if you can recover from squatting 5 days a week you should be able to recover from arms every day. I'd watch out for tendonitis though.