One of the things about ADHD is called "time-blindness." It's one of the reasons why people with ADHD are impulsive and inconsistent and distractible. For us, there really is no time but the present. We have really poor memories. For me, the past is like a movie I watched a long time ago, not something that happened to me, personally, at all. And I mean, a few days or weeks or months ago, let alone years and decades. And we're no good at envisioning the future, either, which makes planning for it hard, and sticking to a plan even harder. On a smaller time scale, we don't naturally track the passage of time throughout the day. We have no idea how long things take, even if we've done them every day for years. We're always running late. We very often get hyper-focused on the task of the moment, and completely lose track of its relative place or priority in the overall scheme of the day. It's a whole thing.
In my Rule of Life, I promised to keep on what I was doing when I wrote it, which was to pray all seven Hours of the Divine Office daily. That's not a whole duration of seven hours, it means at seven hours each day. It means that seven times a day, I would stop and read (usually chant) a litany of psalms and prayers and short readings from Scripture or other religious texts. I used it deliberately as a prop for my time-blindness, because it created a natural framework for my day around which to create a loose schedule. I downloaded a church-bell ringtone and set it to ring for the Hours. I loved the way it broke up my day, continually recalling me to, first, my intention to live prayerfully, and then second, back to whatever program I had invariably gotten side-tracked from in the interval since the previous Hour.