I have meditated off and on for a few years, but only recently began meditating, correctly (I hope!)
In the beginning I found it hard to place my concentration in one place, everything would bother me.. tiny itches, thoughts running through my head like freight trains. etc.
After more practice, it's become much easier to maintain my concentration for longer periods. I've found all of those thoughts act like magnets for your attention.
as the meditation deepens.. I notice the thoughts sort of rise and fall like waves on an ocean.. and I become detached entirely from them.
The first benefit I noticed that motivated me to continue were states of relaxation and happiness after meditating.
I have since noticed improved concentration on daily tasks,
I have also noticed that my mind is calmer, even when I have not meditated,
I suppose a general sense of well-being and happiness as-well.
I hope any of this was helpful and answers your question.
"We know nothing at all. All our knowledge is but the knowledge of schoolchildren. The real nature of things we shall never know." - Albert Einstein