I passed the 301 test back in 2013 and was working on renewing it with the CASP, but life got in the way and my Sec+ expired.    Fast forward to 2019 and I decided I wanted to renew and it would be easier to take the 501 than try for the more advanced tests.   
I've been a tech at a small shop dealing with small business clients for the last 18 years, but our clients are small enough that we don't deal directly with most Sec+ subjects all that often.  That makes it tough to retain the details, but I have an interest in the material so I enjoy studying it when I have the time and energy.
As most have done, I digested Darril's 501 book the same way I did with his 401 book and was scoring 90% or better on all the free practice tests I could find.  I skipped Messer's vids this go-round, although I watched them all before taking the 301 a hundred years ago. I also have been a Security Now podcast listener for many years... which helps keep my vocabulary up to date.
Good news.. scored 817 and am now Sec+ again.
Bad news....  Holy  #$
@*+,  COMPTIA tests have evolved while I was away.
I honestly felt I guessed on half the questions (educated guess).  The material was familiar enough, but the format of most of the practice exam questions I took felt terribly out of date compared to the actual questions.  The modern questions are much more geared to applying the knowledge than knowing the definitions.  That's a good thing, but I felt very unprepared and was seriously concerned about throwing $300+ on the floor..   LOL
All I can say is.....  Do Darril's labs, play with the software tools, read some log files, and sleep with your book under your pillow!
Best of luck..
Abramsgunner
A+, Net +, Server+, Sec+, Sonicwall CSSA, Lenovo Server and Thinkcentre