No, it is not okay to drive in 4WD all the time. Doing so can cause serious damage to your vehicle and may even void your warranty. When driving in 4WD, you are essentially forcing your car to work harder than it was designed to. This can lead to premature wear and tear on vital components, and can even cause your car to overheat. If you must drive in 4WD, be sure to take breaks frequently and never use it for extended periods of time.