Base Layers
Underwear is best merino or nylon. Ex-officio makes good underwear that is extremely durable. Merino is not as durable but has better odor control, and must be bought from a reputable non-chinese manufacturer such as Arcteryxor Icebreaker. The bottoms must be synthetic, the upper shirt can be synthetic or merino wool. Socks should always be merino wool, either Darn Tough or People Socks, or any merino/nylon hybrid with at least 60% merino wool.
Mid Layers
For this polartec grid fleece is the absolute best option. It is often expensive unless you get surplus. In a pinch any thin fleece pullover will work as long as it is durable and lightweight. Insulating Layers Polartec High Loft is the best performing ultralight insulating layer. It is possible to find from outdoor companies but is rare. Surplus is usually the best option. It is designed to be very breathable so when you take off your shell layer it can dry out and you can cool off. A second less breathable layer such as an Arcteryx atom It can be added to your system if you expect very cold temperatures, but the lv 7 is too much.
Shell Layers
For durable shells there is multicam uniforms or similar synthetic shells that perform well to protect against scratches and snags and act as a wind break. The high loft jacket needs a shell to stop wind, and adding one doubles its insulation value. For rain and snow, only goretex should be chosen. There are many different competing fabrics but most have not withstood the test of time and they often de-laminate within two years. Goretex paclight is the best shell fabric weight wise, but care should be taken to keep it clean, as over long periods of time skin oils can damage the membrane. Some versions come with a net layer to help prevent this, but its best to wash it once a month when used heavily.
All clothing used must be synthetic and designed for layering. The gold standard is Primaloft and Polartec fabrics. Polartec is much more durable than cheaper alternatives, and doesn’t pill or shed. Make sure you are getting authentic Gen III ECWCS layers and not knock offs from companies like rothco. It will have a tag if its authentic. Cheaper versions will not have ir coatings as well, which is important because many synthetic fabrics glow under ir illumination and are easily visible to night vision. All of these layers should be washed with appropriate detergents (kookaburra wash for merino, tech wash for goretex) and always air dried, never in a dryer. This will ensure these layers last a lifetime, which they easily will. You only need 1 of most layers except underwear and socks, but having an extra top base layer isn’t a bad idea. Gloves that fit you well are also a must, along with a pair of lightweight hiking boots.
This is based on the ECWCS Gen Ill system, which was heavily researched and mimicks the system Arcteryx and other outdoor clothing companies use for mountaineering.
Fabrics The single most important factor in clothing choice is the fabrics. There is no comparison between usa/european made fabrics and knock offs. Price also isn’t a factor because authentic polartec fabrics can be bought used for very cheap from surplus stones or thrift shops. Goretex is coming down drastically in price as well. It is worth it to find good authentic fabrics, as they will have the best warmth to weight ratio, compress well, and be far more durable than cheaper alternatives. For polyester based fleeces, nothing beats the different polartec fabrics. For insulation primaloft is very good but there are other atematives that are just as good. Down should be avoided for insulation in clothing layers, but can be used in sleep systems. It completely looses its insulation value when wet and is nearly impossible to dry in the field. Goretex will stop breathing once the outer layer wets out, so make sure to maintain a good coating of nikwax water repellant once a year. Usually only the shoulders wet out where the pack straps push water into the fabric. It will still not leak however Polyester should only type layers, because its abrasion resistance is low. Nylon is the top choice for outer shell layers (both tops and pants) because it is extremely durable. Companies often cheap out by switching to polyester or poly cotton blends. In modern ecwas clothing there is often aramid whichis as durable as nylon but more fire resistant. Make sure to check and verify that either the fabric is authentic, or that it is official gen 3 ecwcs clothing.
Alternatives Modern ecwcs genij isn’t the only way to get very good quality clothing, there are many outdoor companies that use the same fabrics, often with better features and design. It will cost much more though. The ecwcs system base layer could easily be improved by using merino wool, or the best of both worlds: Polartec Power Wool. Never take a company at its word that they use the best, as they often try a cash grab when they get popular. Mountain Hardwear for instance made a “monkey man” jacket from high loft polartec and it was known for being the best lightweight insulation layer for years. Then they switched to a cheaper chinese made fabric that “looked just like polartec” and it failed after a year or two of use (the older version lasted 510). It was only slightly cheaper to purchase as well. They have since switched back. Arcteryx and Crye are both reputable manufacturers, and often store brands have a gem in their collection that is made well and cheap. It is best to search on amazon for the fabric instead of brand in most cases. Arcteryx rampart pant, atom It jacket, and rho Itw line are all solid pieces that can be used around town. Goretex gaiters are also a valuable addition and amust in snow and mud. For city/suburbs, pick earth tone versions of these fabrics.