Gilets might be a bit taboo with some riders, but there can be no doubting they are great in cool or changeable conditions. Gilets provide a similar level of protection to jackets, but without the sleeves to help breathability making them great for keeping your core warm on cooler days and your arms cool on milder rides.
A lot of cycling gilets also have high-visibility detailing or colouring, making them great for commuters to quickly put on over a jacket or jersey when the sun sets to help aid visibility in low-light conditions and to make them more visible to other road users at busy times, such as the morning or evening rush hour.
It's fair to say that cycling gilets are pretty versatile then, and this makes them great additions to your collection of cycle clothing. When you can't work out if you should go with just a cycling jersey or go all-in with a jacket, a gilet or cycling vest (whichever term you prefer), might just be the perfect solution.