I've done my best to keep a copy of all my records, but I have them mostly on paper. I started out keeping them organized, but over the years they mostly went into stacks - and not in any order. When I filed for SSD, I wanted to hand them copies of my records (I had made extra copies of most of the older ones before I left work, when I had a copier available, but now I have to go to my cousin's and use her printer to copy, which is really slow but free!) so it forced me to start some half way decent organizing. Guess I'm old-fashioned, but I started putting them in folders by each doctor, and then separate folders for blood work, etc. For me, I find this easier because I can pull out what I think will be the most pertinent info. to take to a new doctor, so as to not overwhelm them. I tend to take summaries, etc., test results. But however we store them I think it's important for us to keep copies of our records because I find that frequently they don't make it to a new doctor's office, or to other places they are needed. That's why I brought all the ones I had to SSD.
I do think it gets overwhelming, to say the least, as most of us see so many doctors, have so many tests, etc. But if we're not our own best advocate no one else is going to do the job.
Also, whenever I start with a new doctor, I ask to sign a release form so copies of records can be sent to me. Most doctors will do that at little or no cost, especially the ones I'm currently an active patient with. Past doctors are another story, but if you put "continuation of care" as the reason you're seeking a copy, they often won't charge because it's saying you're taking them to other doctors. A few places have given me a hassle, and in a few cases I've had to pay, but mostly I've been able to get them at no cost.