Patagonia Cap 4 vs IceBreaker 260

"I would just like to say that in regards to durability, high quality merino is VERY VERY durable. I have been wearing merino socks, underwear, and t-shirts every single day for the last year, and none of them have any holes. Of course, you have to buy a good brand. For socks I use darn tough, and for shirts/undergarments I use Icebreaker. The stuff is just very well put together."

High quality merino socks are in a different category. They are highly worsted. Wool has such a low tensile strength, especially when wet, that long ago people figured out that you had to tightly twist multiple strands of fibers together to increase the durability OR felt it strongly so that the fibers interlock creating strength in numbers/unity.

Darn Tough socks for example, use very highly worsted wool, and because it's thicker yarn, it will be more durable. If you had a baselayer made out of equivalent yarn that is used in their typical socks, it would be rather heavy and thick. You don't notice this, because it's such a small item, and typically there is a moderate amount of nylon added to increase durability and strength.

This does not apply to thinner merino, like many baselayers. Sheep's wool has literally one of the lowest tensile strength of any textile, and it's especially weak when wet.

There have been plenty of accounts of people here and other places that went on thru hikes, and had their thinner wool baselayers in rough shape by the end. Synthetics generally are MUCH more durable per similar weight, weave, and volume.

Now, if you're talking a Filson coat made out of thick, felted wool, that also will last a long time and be very durable and strong.

Like most things, wool is relative. Black and whites need not apply. I'm speaking from a combo of experience and research. I'm not a wool hater. I like wool synthetic blends quite a bit–particularly MeCo stuff. For the budget conscious, Dri-Release wool is ok, but i wished it wicked better. One could lightly sand the inside to increase wicking.

Honestly, I am not sure what treatment if any that Capilene 2 piece had. It was several years old, so may not have had any.

As for durability, I have one merino 150 weight Icebreaker t-short that I wore quite a bit and it got a good number of small holes. I am not too upset, since it's also been bleached by sun and retired into my running t-shirt.

I am with everybody on wool not being all that good a base layer in other respects. It's not as comfortable, stays wet longer, stretches when wet, etc. Yet, some synthetic pieces pretty much need to be thrown away after a single trip. Just not working for me.

All that said, merino also better controls the regular sweat smell after a several days of sweating and sleeping in the same shirt. Not odorless, but reasonable.

P.S. I have zero problems with synthetic fleece, BTW.

"Honestly, I am not sure what treatment if any that Capilene 2 piece had. It was several years old, so may not have had any."

Patagonia started to use Polygiene silver salt treatment in their fall 2013 line and thereafter.

Before that, they were using Gladiodor, which was not as effective nor as long lasting/durable. I'm not sure what, if anything, was used before that.

Supposedly, Patagonia spent some two years researching various different anti-odor treatments before finally deciding on Polygiene. They settled on Polygiene because they had a good established reputation in the medical field, because of the effectiveness and durability of the treatment, because they used recycled silver and very little of it which made it much more "eco" than many other silver treatments.

Silver has long been recognized as an effective broad based and in many forms topically safe anti-microbial.

Ime polygiene works fairly well, but that is on short trips–no longer than a week (in Costa Rica over about a week, i wore an OR Echo LS shirt for much of the trip, sweating almost constantly in it)–i've yet to do a longer trip with it. My sense is that it will work well for keeping down odor caused by microbes, but will not do anything for the eventual oil buildup in and on synthetics that start to smell from going rancid. Gently rinsing often may help some with that?