Depends on how old it is. Mine’s a 1995 model. I’ve measured its energy usage and a new fridge would pay for itself at around 9-10 years if I bought a basic model*. That’s around the lifespan I’d expect from a new fridge. So I’ll just keep using the old one until it dies.
(*) Current fridge is a basic, low end model, so assuming I replace with a similar basic, lower end model. Payback would be much longer if I upgraded.
And what, have twice the fridge space for slightly less than twice the energy cost?