Skin needs to be clean. Sort of.
Ironically, the more aggressively you clean your skin, the more likely it is to develop issues like acne, scarring, redness, irritation, dry patches, etc, because you're actually stripping away layers of skin and the necessary oils they produce to guard against the elements. In essence, you're getting rid of the good stuff. Not to say that you should necessarily go without. For instance, getting your face licked by a grown man is probably good grounds for a nice scrubbing, but there's no need to book an appointment anywhere.
Facials are pretty aggressive with steamings, peelings and extractions designed to remove minute layers and expose new, fresh ones that are far more sensitive and prone to damage. Done repeatedly, texture and tone will start to denegrate making you think you need, guess what, another facial. I'd say once to maybe twice a year is enough. Any more than that and skin will start to thin out, becoming more delicate and prone to infection than when you started.
If you take the time to remove makeup properly, exfoliate lightly and keep strange tongues at bay, you should be able to go without facials.