Set a monthly retainer fee for a client.
A retainer trades a modest discount for guaranteed monthly revenue and priority access. The fee is the discounted rate times the hours reserved, and the overage rate is deliberately set above your standard rate — otherwise a client can treat the retainer as a floor and buy the rest at the same price, which removes any reason to commit hours in advance.
Retainer pricing
Monthly retainer = hours included x standard rate x (1 - discount/100); overage rate = standard rate x multiplier
Five to fifteen per cent is typical. Deeper discounts only make sense when the commitment is long, the work is predictable and payment is up front.
Preferably not, or only for one month. Unlimited rollover turns a retainer into a prepaid balance and destroys the revenue predictability you priced for.
Because it protects the retainer's purpose. If extra hours cost the same as reserved hours, there is no incentive for the client to plan work in advance.