A mudguard is a must to stop you getting a big stripe of mud splattered down your back at the slightest hint of rain. If you want to avoid having to change your entire outfit after each journey, you need the right mudguards.
There are several criteria to consider, from your use to the mudguard's position.
1. Mudguards Based on Usage
There are several types of mudguard available depending on your bike type.
Hybrid and city bike mudguards are long and thin, covering the entire back wheel and/or front wheel.
Mountain bike mudguards are wider and shorter than those designed for the city. They are also stiffer and more stable, which makes them better suited to riding on rugged terrain as they won't touch the wheel.
2. Mudguard's Position
Mudguards protect cyclists in different ways depending on whether they are fixed to the front or back.
Rear mudguards are generally fixed behind the saddle, above your back wheel. For mountain biking, go for a model that fixes onto the seat post. This kind of mudguard protects you from mud a bit less, but mud is the lesser of two evils - the advantage is increased sturdiness so it won't touch the wheel at all.
On city or hybrid bikes, the mudguard tends to attach to the frame. This fixing system is reliable and also protects the cyclist.
Front mudguards are fixed to the fork or underneath the frame to offer maximum protection from dirt and splashes. They therefore keep you safe by protecting your vision.