To Varnish or not to Varnish? What do you guys think and do yourselves?

The one thing I have never been totally sure about is whether to varnish my finished miniatures or not. There seems to be a general consensus that varnishing models does a better job of protecting them against hazards than not doing so, which seems logical! But while a big one, this is the only real positive I can see to do it though, so is it enough? There does however from reading a lot of guides seem to be no consensus on the best products and methods. So I wondered what the other hobbyists around do? Do you even bother?

I have come across numerous posts on many sites of spray varnish disasters. This has made spray on varnish a definite no for me. I spend way to long prepping and painting my miniatures to ruin it trying to cut corners at the last stage. So I have been testing out a brush on product and its this:

Vallejo Acrylic Matt Varnish. I had seen it recommended a few times and as I wanted a matt finish I thought I would try out a bottle. A test model (In my finished scheme, loving the way it looks btw!) got a going over with it today. I was going to take before and after photos to show what effect it had on the colours but I forgot and started covering it with varnish! oops, never mind! I can tell you now there is obviously some colour change, but its not massive and actually the very slight shine this varnish gives seems to make the guy pop to me! So its actually a bonus rather than the negative affect on the colours I thought it would be.

I wasn't easy on the guy! I slapped it on, neat and thick and left huge amounts in the recesses. I wanted to purposely see if I could ruin a model with this stuff (Although I understand the cloudy complaints can only happen from spraying?). It doesn't seem to have any adverse effects, I could see no differences in colour or discolouration where I had put it on thick and it was hard to tell how thick the varnish was in different places with the naked eye in normal light, so again all good.

One I'd prepared with varnish a couple of days ago I chucked around a bit and dropped on the desk from height. There definitely seems to be much more resistance to chipping than paint alone which with our metal guys is important. One thing I have found is that the varnish is relatively soft though and not very resistant to scratching. Certainly seems not really any better than without and you have the added problem of, with the varnish on, its now very hard to touch up a scratched model.

Some people have mentioned you need a gloss coat first then a matt coat to get maximum hardness. Can anyone confirm to me this makes a noticeable difference over matt alone?

Weathering powders seem to work ok over the varnish (although I'm a complete novice with them), while obviously you cant brush varnish over the top without ruining your effect.

So here's my big question to you if you answer no other: Am I making a real difference to the life of my miniatures if I use this varnish on them all, or am I lulling myself and actually, when I just inevitably damage them, have I made it almost impossible to repair it without looking crap?

What do others think?

Thanks in advance guys, I ask this advice while the first 5 of my platoon are almost finished on the desk and I can't add basing materials until I decide to varnish or not!