Should I change engine mount rubber in stock '73 318 V8?

What are the pros and cons of changing the original rubber with polyurethane inserts? The original factory rubber appears OK. Does it wear out after 50 years? These engine mounts have the steel cylinder surrounding the rubber. The original rubber is removed with a propane torch and the new polyurethane inserts slide in. This is a stock 318. Not a muscle car. Thanks.