As Floss knows, I'm definitely a big fan of Zipfit liners. I have feet that are very wide in the front half, narrow around the heel, not very high and with some lumpy boney parts. With these feet, getting a good snug all round fit with standard liners is not possible and I find standard liners pack out and become loose too quickly. With Zipfit liners I can use a boot with 4mm to 6mm narrower last, as the toes box made from neoprene is much softer and thinner than standard liners. I used Zipfit liners in the early days when they were very hard wearing and you could get 1000 days of skiing out of them. The materials they use now and the way they make them, has moved more towards performance and away from longevity, so now I expect them to last more like 300 to 400 days. Zipfit have 2 touring liners now, the GFT (harder wearing version) and a new lightweight liner (definitely won't last as long). Popular sizes in the GFT sell out very quickly at the start of the season and last year, most sizes were sold out by the start of January. Using Zipfit liners is a process. They need professional fitting over 2 or 3 sessions. An initial heat and fit, followed by a couple of weeks of skiing and then a return to the shop for feedback and adjustments (adding or removing cork to/from the tongue and the 4 ankle pouches). You may then need further adjustment after a further 4 weeks or more of skiing. If the liners pack out over the seasons, more cork can be added as needed. I have noticed, they do pack out (at least, initially) more than they used to. I think this is likely due to changes in the materials used (more neoprene and marino wool). Also the material used around the outside of the heel, does not seem as hard-wearing as it used to be. Increasing the amount of cork in the tongue, will increase the forward flex stiffness of the boot. Using Zipfit liners is not a guarantee of comfort, and they are not quite as warm as standard liners, but if you struggle to get a good comfortable fit, they might be a solution.