Before I continue with The end of an era, I thought I'd answer the questions I got.
@jasonleow: Do you wish you had spent more time (more than your current 1 month) in one city? Or spent less? Why?
I would not have gone any less. Travel days are the most tiring days, even when you don't get hit with delays. I wouldn't want to be on the move so frequently.
I also think you don't really get to know the city if you stay less than a month. Especially because we're working full time, we really only have the weekends to explore.
I also don't know if we'd stay longer than a month. In Europe, we were bound by the Schengen Visa limits which only allowed us to be in the area for 90 days. If we stayed longer than a month in a city, we'd only be able to see two cities, max. We felt pretty good about one month.
@demi: How do you determine when to move to the next place?
We usually pre-plan how long we're going to stay in each city (usually one month). This is so we can plan a little ahead for our next city. If we book too close to the date we want, flights are expensive and good Airbnbs are gone.
@demi How long do you stay in one city, and do you explore it fully before leaving?
We usually stay one month. I wouldn't say we've explored any city "fully". Cities have so much to offer! Depending on how you like to travel, you can optimize for different things. For example, we care more about getting to know the city from a local perspective than seeing all the "sights". I like going to markets and just wandering around small streets. Some things I would consider a must-see like the Alcázar of Seville. Do your research so you don't miss out on what you want to see. I would be happy to go back to any of the cities we visited.