I've gone through way too many Driveshafts to admit and I think I've finally hit the sweet spot for S13 chassis.
I used to go through at least one driveshaft every drift day...
So a few steps I've taken to stop me killing off shafts so frequently:
Subframe raisers:
Higher subframe results in less distance from diff to wheel, which will help with driveshaft stress. My car came on Solid subframe mounts which have like a 15mm spacer built in at the top. I just removed the top part of this and got a free a free subframe riser kit. I added a big washer for peace of mind but heard of people not running them and I don't imagine it does much.
Also all of my arms are straight, no luxury of kinked arms. I had to bash back a few lips to stop them from fouling the arms. Also I had to chop down the end of the subframe bolt to stop it hitting the Toe arm.
Normal solid subframe mount on left. Demonstration of the upper mount removed on right.
S14 shafts:
The lower your car is the longer your shafts need to be as the wheels are further away from the diff. Theres some bolt on 10mm adapters to you can buy to take up this space but these aren't great. I thought that if an S14/S15 has a 10mm wider track, it will have longer driveshafts... I went out and got some shafts and right enough the S14 shafts are 10mm longer. Bolted these up and instantly saw a massive decrease in how much I went through driveshafts.
Since I'm still on an S13 rear subframe I will get the benefit from this as its not an extended track. I've read that to counter this on an S14/S15 subframe etc you can shorten the rear lower control arms. Nothing I've dealt with before so can't comment.
Broken shaft reuse:
Two things to point out. The only difference on S14/15 3x2 shafts is the centre axle being 10mm longer. If you buy a set of S14 shafts and kill a CV joint you can swap out the CV joint from an old S13 set onto your S14 axle and keep the longer driveshafts.
Also the inner and outer CV joints are exactly the same. I went through my shaft graveyard and ended up with a load of fresh shafts from swapping outer CV joints from knackered shafts onto the inners. Wish I knew this before I ended up buying every s14 shaft in Scotland.
5x1 vs 3x2 shafts:
Ask the internet engineers on whats better between 5x1 and 3x2 shafts. Everyone will say 5x1. So when I bought a 4.3 diff with 5x1 outputs for an R33 I thought I'd make the jump to 5x1 shafts also.
100 miles into my first journey with 5x1 shafts I kill off the NS. Then 500 miles in the OS goes. Swap out to another set for a Rockingham drift day. Again kill off the NS. This was with all other normal mitigations that stopped me killing shafts constantly. I ended up going back to 3x2 shafts after doing those 3 shafts in rapid succession. I don't know why the CV's were so weak on my car but yeah, they sucked on my car so I won't be going back. I was going to re-core the 4.3 but decided to just sell it instead and stick with my 4.1.
Exhaust heat:
I covered this in the Exhaust post but it crosses over since it directly impacts the shafts. The heat from tucked exhausts will see off the CV rubbers pretty quickly so I have welded on 2 M8 nuts onto my subframe and created a heat shield.
Pretty much everything I've done for keeping my Shafts good.