What are the basic features you check before you purchase a mobile? 

These types of questions are generally asked to see how you make decision and how's your thinking, etc:

The following are the different things I check before I purchase a mobile

Price: The first thing, I check is whether the price of the mobile, whether it is falling in my bucket.

Quality: The second thing, I will go with the quality of the mobile .

Reviews: I check User reviews to check whether the customers are recommending or not.

Easy to Use: The mobile is easy to use or not.

As Per my needs:  I will check whether the mobile is suitable for my needs or not.

Battery: Long lasting battery and ability to charge quick, so that when I travel it shouldn't be a problem or there should be a need to carry an additional power bank.

Display size: I generally prefer large screens, so I check the screen size. 

Storage: Has enough storage.

RAM: I prefer choosing minimum 6 GB RAM.

Processor: Processor having good speed.

Camera: Front and Back Camera and their resolutions I check.

No of Sims: I prefer two sims.

Security Features: Different features available in the mobile to make my mobile secure.

Other than this I will compare this with other popular mobiles in the market to select the best one in the market.