Is it better for you to repair a few patches of siding, or replace everything on the outside of your home? This really comes down to the build quality of your home as well as the age of the siding that is currently there.
In most cases, for older older homes it may make more sense to invest in new, modern materials instead of spending money on repairing the siding you have. This way, you’ll have new siding and protection for your home that will serve you for decades to come, as well as a new refreshed look raising the value of your home.