Salmz, everyone and a ( bit of a late) 'Ramdhan Mubarak'
I hope and pray everyone reading this is in the best of health and Imaan,ameen

I was wondering how comes a lot of people read just 10 rakaats in Taraawih,
I noticed this the first time when I went to perform Umrah and was shocked to see that so many people around me fold their musallahs and and start making their way home after the first 10 rakaats.
Is it cos they follow a different Imaam???

Regarding this I was wondering if its ok for my younger sister to start off reading her Tarawih with 10 rakaats and gradually she will read full 20 Inshallah.It's a bit hard for her with her going school and with the fast being quite long.

And my last question is on certain days I feel very tired.Especially when its time for Tarawih which seems to start as soon as I finish eating,would it be ok to read just 4 farz 2 Sunnah and then start tarawih and read witr at the end rather than read all 17 rakaats of Isha.So basically is it ok to read just 9 rakaats of Isha aswell as tarawih)???

Thankyou so much for taking the time to read this,
I am awaiting your response very eagerly.
Jazakallah-khair