I'm coming up on close to 3 years of continuous barbell training. I've always lifted either 3 or 4 days per week, never more than 4 hours in total. Consistency has not been a weak point of mine. To echo some of what others have said.
1) Power of habit. Hitting the gym is, among other things, personal maintenance for me, not much different from brushing and flossing. I've just made it something I do.
2) Prioritization. Family obligations first, work second, gym third. That leaves a lot of things I'm willing to let slide before I skip the gym. Dishes and kitchen clean-up are probably the most common thing that I will put off until the next day, but I've also missed out on MANY after-work happy hour gatherings.
3) Planned deloads. Having a week where I know I'll have more time and energy for errands and chores helps me stay on top of life.
4) Making it time-efficient. I'd love to go lift at the powerlifting gym 30 minutes away, but that's not realistic for me to fit into my life week-in, week-out. So I lift at the local joint, because it is a 3 minute drive from my office. Right now I'm doing 4 day upper/lower, and none of these take more than 45 minutes, unless jaw gets worked that day too. When I was doing 3 day/week full-body I was taking closer to an hour, but I could probably do those workouts in 45 minutes now too.
5) Work/life balance. Prior to taking my present salaried position, I was an independent consultant. This had me living much of my life in hotels and eating most of my meals from restaurants, earning me a body that reflected that. A major reason I took this job was to make personal care a bigger priority. I made this known to my employer. My boss knows I lift after work, and he knows it is important to me. So on the rare occasions where I need to put in extra time, I don't have to sacrifice lifting. I've even came back to the office sweaty and smelly after the gym to do what needed to be done. My boss is fine with this because I was up-front about my priorities and the work always gets done.
6) I'm not doing Jack Shit. This is a Wendler 5/3/1 template, which consists of just going in and doing the big lift for the day (squat, dl, bench or strict press) and then leaving. I've ran this for a few stretches here and there, and I'm sure I'll run it again in the future.
So to answer your question of...
I've gotten to the point where there isn't much decision to make. It is just what I do unless something very important comes up, and even then I just lift at a different time, if possible. I also have a basement gym that doesn't get used very often, but is there for snow storms or days where I'm really busy. Even on my busiest days I can find 30 minutes to go downstairs and accomplish something.
As an aside, from one pale guy to another, make sure you're getting your vitamin D, especially during short winter days. I didn't for a long time and noticed a very significant shift in mood, energy and general feeling of well-being when I started taking it.