Is there any person who was a day scholar in IET Lucknow? What is the experience living outside..what are pros and cons as I'm also deciding for civil services from first year.

Yes, there are many students who were day scholars. A few of them were local and some of them lived outside the IET hostels. Make sure you take a room near the institution. If you plan to stay outside, make sure you are financially stable to keep yourself punctual and healthy.

You will find rooms on a rental basis near your college, check if you can afford to stay there. Plan your finances well. Do not reside further away from the college. If you stay outside hostels, you might face some problems with reasonable food options. Otherwise, everything else will be easy.