As a general comment on repeat head injuries, it seems to me very hard (impossible?) to foretell how much harm can come from repeating TBIs/PCS.

The first one or main one in your life (if you're here reading this) was probably much worse then you could have expected.

Now you're partly wiser, (if you're reading these postings and you'll have had loads of other experiences to put you in the picture to some extent), but I reckon these things are certainly true --

-- Contact sports (and some others) have a high risk of TBI/PCS
-- If you've already had a significant TBI/PCS, your brain is more sensitive to and more easily more harmed by physical trauma
-- Repeat injuries are often much worse, and/or happen more easily (=with smaller impacts).

It seems EXTREMELY hard at first to sacrifice sports or activities you love and are accustomed to, in order to keep safe, to avoid a mere chance in the future, but the hardships of re-injury are awful.

I had my injury from a head-first fall off a rearing horse (unhelmeted) onto farmyard concrete. A complete life-changer, to put it ridiculously mildly. That was 21 years ago. Slowly, slowly, I've got a new positive life focus, but the relevant things to pass on are --

-- I had just one probably small impact seven years ago, which immediately sent me into coma, (and with pre-traumatic amnesia, which just means your mind can't access exactly what happened leading up to the impact) ... that was VERY cautionary and set me back

-- over the years, I've known several TBI people with re-impacts, two in particular are always in my mind, because I know the specifics of their re-injuries more closely -- each one, from just a "modest" re-impact, lost very much quality of life, permanently

-- lastly, being "in the know", knowing that your brain is vulnerable, has got to be an inhibition when you're playing a contact sport with an injury risk. It will hold you back a bit, unless you choose denial or a sense of oblivion.

Keeping out of contact sports after having had a TBI is necessary, and gets a whole easier when you've taken a new direction. I hope that anybody reading this for whom it's relevant, can really find their own mechanisms to be safe. Re-injury just gets worse and worse. Maybe it's a bit like the Richter Scale for earthquakes, going up just one point is ten times worse -- but the one extra point with re-injuries comes even with less impact force.

Mind your head -- it holds your mind, and all that.
Have lots of luck, but arguably nearly all luck is pre-arranged (particularly "bad luck"?) ... ultimately it's up to ourselves.