Knight helmet,Starting my studies and practice

I have watched some tutorials over at CGCookie and learned some of the basics needed for modeling so now i want to continue working on my modeling skills.So…how do you do it? :smiley: i hear people doing “studies” of specific objects to get better.
Here i decided to make a knight helmet,seams simple enough and looks interesting for something to start with.
Are those what studies are and how you get better at modeling?
Watching and recreating objects around? or i was thinking i could try to find and download a few good models here and there and try to recreate them.
Here is what ive done so far.It looks good i guess i found a image online and decided to make it in 3D.
Its not perfect as i had multiple reference images of few different helmets so they are mixed a bit and its my first try at a knight helmet.

And while modeling it i found i a few questions im curious about.

Mostly having your mesh or object divided into me it seams a little bit of a cheesy way to do things sometimes,as when you separate it you dont have to worry about the intersecting part and how the topology will be there as they arent actually one part.As i was struggling to make the back helmet look like its made of multiple metal plates and at start i was struggling to do it from a single mesh,extruding the lines to add thickness to it.But i found quickly that,that way its harder to make all the polygons similar size and have a nice flow.So i just broke them into chunks and did them separately not needing to think on the points they intersect.

So i want to know when is modeling like that okay and needed and when is it not okay?
Cause it seams that its a lot easier to just brake your mesh up so you have less issues with the topology.
here is how things are going so far:

I just used a matcap to get it to look this way.But now i dont know how to make those small bumps and dents on the surface of the helm that the texture of the matcap did.I want to make it a game ready asset so i am wondering how to make it look like this on the retopo.
Should i just use a textured brush and sculpt them lightly on their or should i just paint the specular map with the brush in order to get that effect? @[email protected] somebody please help.

And if you have any good tips or tricks that could possibly help me on my journey dont be afraid to say