“I would say revise it every four weeks, but don’t make any drastic changes until the six week mark,” says PT Tess Glynne-Jones. “If you get to six weeks and things are going well – and you’re still making progress – keep things consistent until you reach eight weeks.”

Trainer Caroline Bragg is keen to stress that, as with anything fitness-related, it all depends on your goals. “If you’re just looking to maintain fitness, you can change it up as much as you’d like really, but if you’re looking to gain strength, I would be sure to develop every single session.”

That means doing similar exercises but looking at your rep range and then adding more load. “Then every eight weeks, you should probably have a little check in and change what you’re doing. It’s good to have a complete shake up every so often and do a week of something you wouldn’t normally do.”

How often should you change your weight training programme? Here's what the fitness trainers say