In older time there was qwery keypad smartphone or mobile phone due to which texting of those sentence or any word typing was easy but symbols were limited like # , & and many more while there was no symbol like $, @ , etc etc but in 21 century due google keyboard now we have onscreen keyboard after typing in continuesly for limited time like while using Whatsapp or facebook or any other search we always type onscreen once againg our finger print or whatever dust which settle on thumb or fingers get settled on screen due to which sometimes screen to get dusted . So sometimes to protect screen we must take some precaution ( which I do) which stated below :
1) . Always use screen guard or screen protector for your mobiles so that even if it falls from your hand accidentally then to your second screen ( that is screen guard will get damage) but primary screen ( or main screen) get protected.
2) . Never directly exposed your mobile phone screen because it damage your smartphone or mobile phone display pannel.If you try to expose it directly it to sunlight and suddenly if you take it to some darker place ( where their is no sunlight) while closing or opening of apps you will see shuttering effect .
3) . Instead of using an pencil use stylus or your own finger for writing on screen or signature because it is not necessary to use much more product on screen for writing or signature normal stylus or finger too be used.
4) . Never try to scratch it on screen buy using nail or pencil because it damages the screen.
Also keep your smartphone screen away from electric treatment or ideally not to make screen on for longer period of time because it to damages screen from inside by producing rainbow color fringes within screen.
5) . Always weekly clean your phone by using washed clothes so that at all settle dust on it will be cleaned and reboot your phone too which will free up ram on your smartphone and also it will refresh your smartphone screen from inside. Thus this all tips which I follow and you could to follow it. Thank you.