My last run was 3 weeks ago when I did week 5 run 1. I was about to go for my next run but had a very slight sore throat so I decided to hold off for one day. Thank goodness I did - it turned into a really heavy cold that has only just decided to go away.
I don't run very fast at all and was concerned that running might make me cough so I decided to do a week 1 run again. I didn't cough and am happy my cold has completely gone.
For me that was the right decision as it showed me how much faster, (it's all relative!), I am now running compared to the first time I ran week 1. It boosted my confidence so much that I have decided I will do one day from each week until I reach week 5.
It may be that if I had done week 4 again to test how I feel that might have worked as well - but as there is no rush to get to week 9 I'm happy to redo more runs.
Looking forward to getting back to week 5 and then all the way!