Random question

10 yoe and 20lpa is above normal in TCS.
So first risk would be that of last offs when job market cools and TCS usually fires once in 4-5 years to ensure pyramid curve is maintained.
At her current salary, year on year hike of 7-8% is not guaranteed. More likely range is 4%.

Onsite opportunities will always be there in service companies.

Based on capability,
technical line - would probably retire as architect in the horizontal/ vertical level Management line - anywhere from managing single client (account) to sub unit or vertical/horizontal head.
Promotions in bis service companies get very difficult beyond 10 yoe. She should consider staying in TCS for long term only if her values and Tata values are in sync.

just add 5% percent increase everyyear in that salary

One of my cousins has been working with TCS for almost 22 years..he graduated from REC Warangal (now NITW)..straight Outta college..he stayed in the US for over a decade and now works in India as a tech architect..