An odometer is extremely important for owning a car. There are many indicators which will give you a rough estimate of your car’s mileage, but very few will give you an accurate reading like an odometer. Knowing your exact mileage is important for many reasons: insurance, sales, and maintenance; and a broken odometer can mess all of these things up.
To diagnose where the problem is, inspect your odometer and speedometer. If both your odometer and speedometer are malfunctioning, then there may be an issue with your speed sensors. However, if only your odometer has stopped increasing, it may be an issue with the gears that drive it.
As a result of the plastic gears that turn them, analog odometers have a high propensity to break. Luckily, this is usually a quick fix, unless the gears themselves break and cause damage to the car. YouTuber Chris Fix has created an excellent tutorial on how to repair a broken odometer - armed with just basic tools.