Most healthy cats do not need a fixed bathing schedule simply because they have long fur. They normally clean themselves, with gentle brushing and occasional local cleaning helping where appropriate. A Maine Coon's interest in water also does not mean it wants to be bathed. If the coat becomes contaminated with a potentially harmful substance, contact a vet promptly for instructions and prevent licking if you can do so safely. Do not experiment with household detergents or human shampoo.
Medical skin treatment may involve a specific bathing product and schedule, but that should come from the treating vet. For ordinary care, concentrate on maintaining a comfortable, tangle-free coat and checking the skin. If your cat frequently becomes dirty or stops grooming effectively, investigate the reason rather than repeatedly washing away a symptom without understanding it. Keep grooming and bedding care separate: washing a removable cover can refresh a resting area without unnecessarily bathing the cat itself.
For product comparisons alongside this advice, see Cashmere Comb grooming set and Reusable pet-hair roller. The details below explain their sizes and uses.
Further reading: cats.org.uk; pdsa.org.uk; rspca.org.uk; bluecross.org.uk; cats.org.uk.
Cashmere Comb grooming set
Reusable pet-hair roller