On the running by feel vs running by GPS:
I'd say that for someone starting out it is very easy to go out too hard (of course that's nothing new). Personally in my half last Sunday, I did exactly that and found it reassuring that I was still on/under pace at mile 10. When I then thought about how fast I was running, how it felt, and whether I could manage those last miles as well, I was sure that it would be fine despite feeling like I was really pushing it already.
Similarly during normal runs, I check my watch sometimes to make sure that I am not running too fast. Yes, Daniel's would recommend 7:15 to 7:35 for easy runs and that may feel easy in the moment, but going for ~8:00 is sometimes easier when wearing a watch as a reminder to take it slow.
So while I ultimately would agree that running by feel/effort is better, I think it takes some time to get there and GPS is not a terrible aid.
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I'll post an update on the past week in the next thread but it has been going well. Going for 80 this week up from 60 last week and 73 before and mostly did shorter doubles, two workouts, and all easy runs were on average around 7:40 or so probably. The discussion on Daniel's reminds me that I really dislike longer tempo efforts, specifically again because I fear that I would go out too fast and then don't get the right pace for the last miles because of overexertion in the beginning. I much prefer any kind of intervals and if possible at a high volume. Planning to end the week with some 1k VO2 max work but I'll see how I am feeling tomorrow.