Have a little faith. The gritty mix, properly made, is an excellent mix for trees. I've yet to find any plant that doesn't perform extremely well in it. It's designed for maximum plant vitality and growth because of it's high degree of aeration and excellent drainage.

The gritty mix retains its structure for far longer than it's prudent to go between repots, so it will be the condition of the roots (how rootbound) that eventually causes physiological decline, not soil collapse. No one can say how long your plant will do well in the same pot/soil comb as there are multiple factors that influence growth. I don't think though, that you should be looking anywhere beyond 3 years w/o repotting & the accompanying root work.

Al

Thanks, Al, I made the mix according to the recipe and you're right, properly soaked, the mix feels damp, wet even. Outside the top dries up fast though, I have to start skewering them to determine moisture in the pot.