I was thinking the other day, this garment must represent about the best value for money I have ever spent. They are totally reliable for the purpose and just keep on going. I have two long sleeved and one short. I've had them about ten years. They have been on countless camping trips, fishing, snowboarding and hiking expeditions. When its cold in the winter I just wear them day to day under ordinary clothes for extra insulation. I've been doing a lot of winter running lately. They go on under a normal running top and a windproof shell and its perfect even in the Scottish December. They always keep me warm, dry and comfortable. After a decade they show no signs of wear other than the lettering fading on the washing label. They look exactly like they did when I bought them despite being washed at all sorts of temperatures with all sorts of other items. I can't think of anything else I have ever bought from curtains to a car that has kept doing the business for ten years with no signs of giving up. No bobbling, no loose seams. Its extraordinary. And they are pretty cheap.
There are thicker and warmer base layers available from HH and other manufacturers incorporating marino wool, silk and all sorts of luxury. But for me the point is flexibility. I'd rather wear more fine layers and remain flexible as to what I can take on and off. There is nothing to these but they give you that layer of extra insulation that covers most eventualities, and when it doesn't you can wear two.
Bloody marvellous base layer. So good you probably won't even realise as you never think about them. They are just always there doing what you bought them for.