IT engineer's salary increases in a proportion of the combination of the first project he works on, the skills he acquired while on that project and the desire he has within himself to upskill himself in dynamic environment.
Apart from the above factors, there are onsite opportunities as well if you're performing well.
Now each of the aspect above adds to the possibility of an increase in IT engineer's salary which I would be throwing some light on.
Two perspectives of his life, one being in the same company for 10 years and working in a service based company, if he is amongst the top performers expect around 12 LPA.
Another being a case in which the person is a hopper meaning, he stays in the same company for around 3 years and makes a switch then and continues to learn (assuming that technology is based on Java, Python, Big Data, SAS etc) then you can expect him to be at around 9LPA after first switch considering 3LPA as the starting pkg and 8 percent hike for 2 years.
Then @15.5 LPA after 2nd switch and around 21 LPA after 3rd switch and total experience being around 9 years.
There are avenues to accumulate wealth if you stay for long in a single company and you go onsite(client's location), then your actual increment stays low (1-3%) but you get paid in pounds/dollars which compensates you in every bit. The challenge comes when you come back to India and after 6 years you are still at 6LPA.
So as long as you get decent skills to learn, it more or less depends upon individual's priority if he wishes to stay In India then make a switch, if he wishes to continue in abroad, stay long.
From my personal experience, no matter what your priorities are - work hard, work smart, keep learning and adapting to the changing skills and technologies to stay relevant.