I think the best thing I bought in 2021 was probably Varia. I had been a skeptic for a long time. “I can hear cars coming” was my argument. I took a flyer on a sale and I can’t believe how wrong i was and how much it’s changed my riding. Especially on long stretches of gravel where I haven’t seen a car in a long time and the sound of the gravel has made me numb to sounds. I know when trucks are coming long before they get to me and have time to move to the side before they are near.
If you want a cheaper option, I love Arundel side entry cages and put them on all my bikes.
Even cheaper, Rapha lightweight socks. They fit really well, are light for hot pain caves, and they last forever.