Started running more often, because I'd like to sleep a bit better. Also I do like consistency I guess. I don't know. Running every single day off from work will get old. So far, feeling very good though.
Also started running again with a 5lb weight in each hand. Unlike a backpack, you do get a substantial increase in speed this way, or so past personal experience seems to indicate. Also will build a bit of upper body muscle and if it ultimately slows me down a bit, who cares? After a year of hard work I can't even run a mile in under 6 minutes. I'm not so fast that it matters.
I run so that work is easier and so that I can sleep well and just because being capable of running decently is an essential part of life as this flexh and blood creature, blah, blah, blah. Don't really have to maximize speed....