So, this Mac user sprang for the Screaming Frog, after hearing so much about it (GBP 150, about $ 210 US).
Wow. How did I do without this?
I went on a wild attack on "No Response" and "Client Error" links.
After about a week, I reduced the (previously unknown) errors from about 200 to around 20.
I am also finding out about just how many files I REALLY have. And WHERE they are!
My question --->
Screaming Frog uses the following parameter limits. Everything out of the range is reported.
Title length -------- 30 to 65 characters -- Is this a rule, a suggestion or pretty much arbitrary?
--- I reduced my title lengths after looking at this, and have more to go. They were clearly too long.
Meta description - 70 to 156 characters - Is this a rule, a suggestion or pretty much arbitrary?
My bigger problem, I think, is how slowly Google is changing my site from HTTP to HTTPS (HTTPS= 64% today).
I went totally HTTPS on July 5.
Google previously-credited-Incoming Links are flying out the door, as well, but that could be unrelated.