It was kind of a bonus that I had to rehab my guy for a bowed tendon, because it taught me to love the walk. First in hand, then under saddle, 5 minutes, then 10, and so on. The vet wanted an hour at the walk before we added in the trot work. Then 40 min walk + 5 min trot. He was 4 yo at the time.
Even though he is healed from that injury as a 5 yo, he still loves his long marching walks, and so when it is nice out I head outdoors at least once a weekend for a long hack (1-1.5 hours). This summer was all about learning terrain, hills, in and out of trees, water, tall grass, etc. As much exposure as I could safely manage. I’d go longer, but there are two loops that are about this long and they are just so convenient.
Next year we will hopefully have a day of trot sets and a day of walking as we build fitness to get out and show. The winter is very hard for incorporating walk work, as we are mostly limited to indoor work. As long as there is good snow for riding in, I do like to work in the snow, as I find it to be very good exercise, but very tiring!