12 interchanges from 6 replacements, at least three of the replacements being club-trained players under the age of 21 at 1 January of that year for me.

Fatigue brings about mistakes which reduce quality and intensity. Having more fatigued players on the pitch because you've reduced the number of replacements isn't going to improve the intensity of the competition.

I actually think 12 is too much. And by adding even more subs you're effectively saying players don't need to be as fit as they could be. Reduced numbers of subs brings the focus back on the individual player to be as fit, motivated and mentally focused as possible, and for the team unit to be as disciplined and well drilled as possible.

Team A is playing team B. It's a close game and after 75 minutes the scores are tied. Unfortunately, Team B is marginally less disciplined in defence and hasn't put as much work into fitness and conditioning as Team A, and begins to tire. Team A is still fresh enough to still run slick moves and a minor defensive lapse by Team B sees a match-winning try scored.

Having every player able to rotate the instant he's a little bit fatigued isn't going to improve their determination or motivation. A player who can push that little bit further deserves to stand out. I don't want to see 13 automatons out there knowing they just need to see out their little spell on the pitch - I want to see the hardest working and training team rewarded.

I agree.

When we used to have fewer subs there was more emphasis on players endurance. Being fit enough to play the full 80mins was a thing that was expected, now it's a rarity amongst a lot of forwards.

Personally I think there's more to admire watching a Kevin Ward or a Glen Lazarus playing the full 80 than seeing a lard ar5e like Paleassina doing 10mins as an "impact player". If forwards had to spend more time on the field they wouldn't be able to carry so much weight and would have to work on other parts of their game (making them better all round players). They couldn't expect to make the same impact as they do as a 19st behemoth going hell for leather for 10mins.

You may also find that having to do 80mins means that collisions aren't as violent and there are actually fewer injuries.

I'd say 10 subs from 4 should be the absolute max. In fact I'd bring it down to 8 from 4.

As an old has been I still have not figured out the best way to go, I my day it was two subs & only for injuries.as an outside back it was great as the big blokes tired & we had more space. the previous genaration had no subs & you had the awfull sight of players with serious injuries limping around the field trying to get in the way or make tackles. At least the structured interchange stops the fake injuries & of course players are much much fitter & more drilled & structured so a load of tired players would just make more mistakes thus not providing the same quality of play for the paying fan.

If it is 12 at the moment reduce it to 10, with the goal eventually being 6-8. This was discussed in Aus papers at start of season, with some coaches arguing for 6/8 interchanges (currently 10).