Driving on bad struts can be safe if the struts are not too bad but if the struts are really bad then it can affect the handling of the vehicle and possibly cause you to lose control of the vehicle.
If the vehicles struts are bad then it can be unsafe to drive with bad struts because it can affect your steering and control of the vehicle.
The bad struts can cause your car or vehicle to lean on the opposite end which can lead to you possibly rolling the car over if the struts get bad enough.
If you have bad struts it's a good idea for the safety of yourself and others around you to get the bad struts replaced.
Several things can happen when a vehicles struts go bad such as uneven tire wear, cupped tire wear, bouncy ride, swaying of the vehicle especially in crosswinds and your suspension bottoming out when driving down rough roads.
You may also notice a knocking sound from the bad struts when the car or vehicle bottoms out.
In rare cases when a strut goes bad it can cause you to lose control of your vehicle and might even cause an accident because your vehicle cannot stay on the road if it bounces the front wheels off the road.
So your steering can be affected by bad struts as well.
It usually takes a good shop around 1 hour to replace one strut and if it's just shocks then they can usually be replaced within 30 minutes for each shock on the vehicle.
Struts can be a little more complicated to replace and requires strut compressing tools to replace.
If you replace the struts yourself and never have done it before then it might take you a few days to replace them.
New struts cost around $100.00 to $200.00 each depending on the make and model of vehicle.
New Shocks are usually around $30.00 to $60.00 each depending on the make and model of vehicle as well.
Shocks are easier to replace than struts.
Bad struts do not affect your gas mileage.
Bad struts have no way to affect your gas mileage but when you have bad struts your ride comfort when riding in the car or driving the car can be bad.
Bad struts on a car can also cause the vehicle to wear out tires faster as well as possibly cause your vehicle to go out of control.
If you do have bad struts it would be a good idea if possible to get them replaced or replace them.
New struts should cost around $100.00 to $200.00 each depending on the vehicle and if you hire a shop to do the job it may cost you $500.00 to $1,000.00 for parts and labor for all the struts to be replaced.
If your gas mileage has gone down then it's something else such as clogged fuel injectors, bad spark plugs, bad spark plug wires, bad ignition coils, clogged air filter, clogged fuel filter etc.
But bad struts will not cause you to use more fuel.