If the equipment is more than 10 years old, it is probably out of warranty. Though the age makes it more likely to need replacement, the homeowner will also be responsible for the full cost. You can help them decide whether it is more cost efficient to replace the unit entirely or pay for consistent repairs.
When dealing with failed equipment, the best option is often replacing the entire system. However, when if your customer's budget does not allow full system replacement, you can always look into only replacing the condenser. This option allows your customer to achieve many of the advantages of replacing aging equipment — improved efficiency, stable refrigerant cost and new product warranty coverage — without the full investment.