It very much depends if I'm just casually playing, or if I'm a mission to grind xp and dust. The shopping center/Walmart near my house is where I do 80% of my day to day purchases, and I've pretty much figured out all the cluster spawn points and best way to hit them all.
Basically, in about 30 minutes I can do one lap around the shopping center, once down the middle, and then off to the Walmart where there are always two big clusters of 10+ each just chillin. I usually catch between 50-60 in that half hour, without using lures or incense.
Then I'll do my shopping at Walmart or wherever, and by the time I'm done, I'll just hit to two clusters (they are right in front of the store) for another 10-20 quick catches before heading home.
The biggest problem is that there are only 3 pokestops in the mall, so I have to come stacked with lots of balls.