new shoes

"One other question. About how many thru hiking miles do you expect to get out of a good pair of trail runners."

Where are you hiking? It will vary a bit depending on the terrain. For example, a rocky stretch of Pennsylvania AT will be harder on shoes than a well-graded forested Oregon PCT section of similar length.

It will also vary depending on, well, you, and depending on the exact model of shoe.

Some people can get 700 miles or more out of pair of trail runners. Some people get less that 250 miles. It's hard to make a definitive statement about this sort of thing.