I’ve always really struggled with it ( harks back to where I worked we had lads laid off and some drivers were trying to sell there holidays 
) so it never will sit well with me ,I think also the fact drivers say they’ve got all these holidays left and can’t get them In so selling a week, why not have a week off in oct/mob they’ve got there five years in so get 33 and sell the five .
I want more , really can’t see I’d ever sell them , if I had 5 days left I’d book every saturday off till end of year and work tues- fri , I guess one day the bosses will stop the extra 5 days if there not being used as hols