You should do it if your radiators are not functioning well. If you have a good boiler, you don't need to replace the radiators. Radiators can become clogged with dust and dirt, which will affect their efficiency. They may also be leaking or have been damaged in some way. In this case, it's definitely worth replacing them with new ones that will function more effectively. However, if your boiler is still in good condition and is providing heat effectively, there's no need to replace the radiators.

It depends on a few factors, like the age and condition of your radiators, as well as the type of boiler you're thinking of installing. It's always best to get a professional opinion before making any decisions that could potentially cost you a lot of money.