Also the freshness of the developer, as an oxidised developer will be much weaker. Stopbath and fixer times are not critical, but their temperature should be close to 20 . Wash water should start at the same temperature, and can be reduced gradually with a couple of water changes, until cold tap water can be run through the tank for a thorough wash, lasting 20 minutes approx. Film Developer is one-shot, and not reused. Stop and Fixer are recycled back into their bottles, until exhausted.
Water works ok as a stopbath also.