I am in a very hard water area and my clothes and towels go hard after only a few washes. That is the reason I put them in a wash with no detergent or a wash with just vinegar to remove the previous detergent. They don't smell yet and I have given them 3 or 4 such washes. When they need it I will use detergent again.
I wash leggings etc. with normal items and absolutely no perfumed stuff or conditioner at all as it makes sports wear feel clammy and sticky. For golf shirts etc. (not mine) I use a bio spray on the pits or oxy of some kind, but they do not get washed with my stuff.
Hard water build up in fabrics makes them feel itchy, and I do get through a huge amount of white vinegar.
As per my previous post, the crap in detergents is the cause of all this, they add more stuff to make people buy it, it stinks, I can smell my neighbours washing and it isn't nice. Another problem is that phosphates were banned a few years ago, that was what kept stuff soft, replaced with phosphonates and they just don't work.
I have bought many of the eco friendly liquids, found that some of them make the machine smell, and never before had a smelly machine. They also are not that great at removing smells from pits and make a lot of suds, which I suspect is the reason, in part, for the build up of suds in the machine, possibly a reaction to the surfecants in the big name detergents.
Since I found my cottons were going rock hard and itchy I have done a fair bit of research on detergents and it comes down to the removal of phosphates and the addition of other crud. I am also sensitive to the fake perfumes and 'natural ones' I mentioned above, hence using Waitrose Sensitive and vinegar washes. I find vinegar removes a lot of build up, and smells, but do follow it up with a clear water wash.
Never before have I needed to run a second cycle to get stuff clean and soap free, eco machines are not eco friendly in my view, they don't use enough water to rinse anything out so I set the extra water/rinse button and put my stuff through again (clothing and towels). The household stuff and other family stuff I don't bother as it is only me that struggles.
Once a fake perfume is in a fabric it is a bugger to get it out, vinegar, lots of rinsing and fresh air, but many times might do it.