my opinion is its good to have a few natural hair brushes, one large badger or squirrel blender, and a couple red sable small falts, becasue they have been the best for finishing, from my experience.i often dont wash brushes with soap if i know i am going to use them next day. (within 8 hours) just wipe them clean and gently work a little linseed (not stand) oil in. i guess if youve used any sort of drying agent in the medium this would be a very bad idea.
but i have found that every day soap kills the brush faster, and i find this is more true of my cheaper brushes. the most important thing is to use lukewarm or coolwater rather than hot which expands the ferrule (which im sure you know, but no one's said it yet, so maybe it will save someone else a big "oh NO"
. i use the pink soap. i dont use paint thinner or turp to clean them, becasue an old instructor told me this is bad for the brush also. everything seems to be bad for the brush.
the conditionr thing is intersting. i hadnt thought of that. does it change any of the brushes ability to hold paint with conditioner residue on it? wouldnt it repel the fat in the linseed oil? or do you make sure to turp/medium it up first before using again?
jai guru deva om