Despite riding to work since 2011, rain was never really an issue. It was Los Angeles, in one of our worst droughts. If it happened to be raining a lot, I'd just take that one day as a rest day and drive to work. Sometime around 2013 or so I bought a simple pair of strap on Fenders. These worked okay for a day after it rained to keep the spray off. They weren't good for actual rain riding and ended up sending a stream of water right into my shoe if I went over any standing water.
Come 2016-2017 things changed. My route changed and now I was riding along the Ballona Creek Bike path for part my journey. There is always water draining across the path and puddles that would last for days after any rain. There were also some dirt "paths" that to get to the path and once I got to work. Oh and it actually started raining again! With that, I had enough and purchased my first real pair of fenders. I talked to Kyle at Golden Saddle and he recommended to me the SKS Longboards which I purchased from them. A couple hours of install time and voila! (If you don't feel handy, I'd recommend having your local bike shop install them) One of the best purchases for a year round bicycle commuter I've made. I no longer have a pile of dirt on my panniers when I unroll them at my destination. The bike stays cleaner and I can ride when there is rain forecast without a jet of water into my shoe or being covered in dirt. The SKS Longboards look pretty good and I don't notice any rattling or noise from them.