For sure it gets harder because until a few months ago even with an average active day and no particular training I was able to burn well over 3000 calories and over 4000 calories playing tennis. Now that has gone down to 2500 which makes it more challenging because I tend to eat and graze a lot. Most of the time healthy stuff but I still often succumb to the sweet treat and eat too many cereals :O)
ADF is tougher mentally when I work from home or am on a day off because I start craving a snack even though I do not feel proper hunger. I actually have created a couple of options that completely satisfy my hunger with about 600kcal which is the requirement and I find it easy to follow when I have a busy schedule, but harder when I am at home, besides of course being tougher to fit with social occasion vs a regular calorie counter approach.
So far I have been able to do it by planning ahead a couple of times a week when ADF did not interfere with my social life and I was expecting to be quite busy. Last week I did one day "fasting" on Sunday and I still managed to do it but did take more mental effort so not sure this is sustainable long term