This all depends on a number of factors:
The Value of your Property
Your Heating Costs
Your Current Windows and Doors
How Many People Live at your Property and
The Overall Energy Efficiency of your Property
There are other factors, but these are the main ones.
Increasing the Energy Efficiency of your home by “Upgrading!” your Doors and Windows will save you money on your heating costs and there is the added benefit that new Windows and Doors can increase the value of your property (Dependant on your Properties starting value and your current Windows and Doors)
So, the answer to the question is…Yes, in most cases!