You we're probably right to cut back on watering. You definitely want to vary it by season and not water unless needed. You may consider sticking a wooden chopstick or skewer into the potting medium and checking it before watering. Looks like you may have root rot with the consequent loss of leaves and branches. This seems a bit high up for the blackened parts, but it also looks like you still have plenty of green below that point. If you can, I'd suggest taking a photo that includes the soil line and posting it. Depending on how far gone it is, you may just want to hack it up and wait for the pieces to root. Generally pretty easy to do with jades. The good news is that other than the one weakness of overwatering, they're tough as nails and re-root readily. Regarding the store soil, every time I've let a plant languish in the peat based stuff they come in, I've had problems, especially with succulents. I'd definitely pot into something else, whatever the outcome is here. At a minimum, some new compost or peat based soil heavily amended with perlite or similar (wide variety of options for this, of course, so it bears perusal of threads about potting mix). You might also consider getting it better light if possible, the green growth in the bottom of the picture looks very gangly, suggests it's not getting enough sunlight.

"I am sure other reader of this thread will appreciate it as well." It's been very educational for me. I'm really glad you're showing the progress of this plant. The trunk is shaping up nicely. I'm learning about this stuff myself. I don't know if you will be able to use grow lights, but I started growing one that I thought had stalled, under a grow light. The new growth (top set of leaves on the right and small ones out of the left) is so compact, I don't know how I'll be able to prune it when the time comes. This has that slingshot look, which will hopefullybe remedied in the future by doing similar to what Al suggested. You may have missed this part of Al's instructions: Don't allow any buds to grow from the pair of leaves left at the top of the stub. This will force back-budding from the lower nodes from which leaves have been shed. If you're lucky, you'll also get a bud to pop at the red arrow. The good thing is you have great trunk growth which is what happens from letting branches grow. I always had that backwards; I put the plants in small containers to keep limit root growth (supposedly), which will only keep the trunk smaller, and pruned too much too soon, like in my photo above, which is actually older than it looks. Here are a couple of links that I've found extremely interesting. They require a couple of read-throughs for me, and then I'll read them again in a few months, after I've had more experience. https://adamaskwhy.com/2012/08/22/dwarf-jade-portulacaria-afra/ https://adamaskwhy.com/2014/08/11/dwarf-jade-bonsai-techniques/ I'm not sure if they apply directly to you, because you may not be looking to make it into a bonsai tree per se, and these plants are Portulacaria afra as opposed to Crassula, but definitely instructive regarding pruning. I hope this thread stays active. Thanks for posting. Sorry I can't give any real advice yet.

Sorry for not posting these pictures sooner - I had login difficulties and then I got swamped with work. Anyway, here's some mobile pictures (excuse the poor quality) and as one can see the aerial roots are starting to shrivel on the one phal and then on the other phal they are completely dried and shriveled up to the point of, I'm afraid to hear, of no return. I water them quite frequently - every few days - give or take - depending on whether I think they need it or not and also dependent on weather/light/temperature of the day. What am I doing wrong? Thanks so much!

Hi! Thank you Gill and Andy. I had a b&q trip and made the mix you suggested Gill. The roots looked ok to me (white and dry) and they'd grown a lot since I last re-potted it - so I think that's positive. If it would be better out of the heat during our 'heat wave' (hottest day in 9years!? Apparently) I'll pop it in one of the other rooms for a while. I did read the link you sent Andy, very interesting and informative. I admit I never even thought about air availability in the soil! Bought a good quality potting mix instead of the cactus mix. Thanks again. I'll let you know if it's improved in a week or so! *fingers crossed*