MR - Does time factor in to equation?
 

So I have been searching and have found a promising mileage run at 3.4 CPM. (Of course I will share after I book it). However, this MR will involve approximately 27 hours of airport time including flights and will earn approximately 7500 flight miles.

I have found another MR that will cost 4.3 CPM and will net approx 6900 miles for 24 hours airport time.

So in essence, based on my MR calculation I will be spending about $30 more to earn 1,000 miles less.

What would you do?

I wouldn't do a 27 hour MR for just 7500 miles, personally. If you had a day in a new place, or something worth doing, then maybe it would be worth it. You can do a transcon for 5,000 miles in roughly 12 or 13 hours or so. Those types of trips are frequently available at 4ish CPM on most carriers. If I were spending 24+ hours I would be looking for 10-12,000 miles.

Miles and time are sometimes related. For example, if I want the most miles in a run, I might force an extra one or two connections to get 500-mile minimums, which would add both transfer time and extra time to backtrack routes (e.g. BWI-EWR-IAH). The best route I've had to maximize miles while minimizing time was IAD-IAH-SFO-ANC, so any transcon or international route would be your best bet.

3 hours is not that big of a time difference when yiour talking about spending a whole day traveling. I'd save the 1CPM and take the longer travel time

Time factors into the equation based on your own values. I like time in airports sipping on drinks and watching airplanes. I also can spend that time productively either walking for exercise or pulling out the laptop and working on one of the projects that I have going on. So, if you feel like you can make something worthwhile out of the airport time, then it doesn't play as big of a role. However, if time away from your home comes at what you perceive as a cost, either financial or personal, then it might be a bigger deal and a bigger cost.