Dry brushing

I still use on almost every instrument panel in the a/c I build.  Also on the seat and other areas in the cocpit to simulate wear and tear.

ruddratt

For a gunmetal effect on my guns, and for a worn metal look, I use a technique I learned about from reading F. Verlinden's books, and that is to mix MM silver with raw umber oil paint and drybrush it on. You can't beat it for either effect.

A similar technique I use to simulate unpainted steel is to use a flat gray primer, such as Krylon, then drybrush lightly with Testors Steel directly on the primer.  Makes a flat, oxidized color with shiny highlights.

For a gunmetal effect on my guns, and for a worn metal look, I use a technique I learned about from reading F. Verlinden's books, and that is to mix MM silver with raw umber oil paint and drybrush it on. You can't beat it for either effect.

I use it on gun barrels, pioneer tools, tires, mud flaps...all sorts of things.  As they say, a little goes a long way. 

I drybrush, but I treat it as one tool among many. It's a great way to punch up a cockpit (or individual panel within...) or do some subtle work on AFVs. My go-to is Model Master Dunkelgrau, which tends to stay rather understated and has all but replaced my old "drybrush it silver" approach to cockpits. Now scuffs and such are done mostly with a Prismacolor pencil. 

When I was using enamel paints I drybrushed a lot more but my stock of MM and Tamiya acrylics do not drybrush very well (if at all) so i haven't done as much recently.  But, it still has a place in my arsenal.

It looks great :)

LOL.. at least i need to try pinwash tecnique  

I tried BSY's method a few times for fading/weathering but could never get it quite right. And for the longest time, dry brushing was my prime weathering technique for armor. I achieved a look on some builds, especially desert armor, that still looks pretty good these days. Now when I combine dry brushing  highlights with pin washes, mud or pigment effects, and airbrushed dust coats, my AFVs have gotten to a new level of finish. A basic overall black wash is out for various reasons(except in a fewselect items/areas), but an overall wash of Raw Umber for a faded dirty look combined with a pin wash of burnt umber and dry brushed highlights on raised details... topped off with various weathering techniques...

Actually i use extensive dry brush on my models and the washing (panel lines) too

if you don't have an airbrush probably is the only way 

here my extreme work using drybrush to simulate the corsair camouflage fading

Short answer, Dry Brushing is out of vogue right now. There are a whole box full of techniques that have taken the old but respectable wash and dry brush to a whole new level. Many people (including myself) are much more deliberate when painting or weathering. I can honestly say that I have not given a model an over all wash and dry brush in probably 8-9 years. I subscribe to the "pin wash" method of going over the object (tank, car, plane, whatever) one bolt and seam at a time for maximum control. In my opinion, dry brushing has it's uses but again in a very micro managed way. I tend to use it more to replicate scuffing and wear than highlighting detail. Now a days I highlight detail by painting highlights, again very deliberately on raised details or upper surfaces with a wet brush.

Again, it's more a personal preference. I'm not saying it's right or wrong. In my humble efforts to paint hyper realistic surface finishes, an overall "black wash" and dry brushing don't normally come into play.

Just my thoughts, take them as that...

I think the two techniques truly compliment one another. When each is used solo it does have a good effect, but when used together, they really make things stand out. Either a lot, when used with highly contrasting colors, or subtly, when more restrained colors are used.