Backing up contacts in Android phones using Google account

Missing contacts from our phones is very irritating and getting back those lost contacts is even more tiring.

The easiest way to back up your contacts is by using your Google play store's account. i.e., by your gmail account itself.

Go to Settings --> under ACCOUNTS select Google --> Select the Google account 

Touch 'Contacts' to Sync the contacts. If Sync is enabled by default then you don't need to sync manually.

Touching 'Contacts' syncs your contacts

The next time when you change to a new phone or have done a hard reset, just sign-in with the same Google account and it restores all your contacts.

It also gives you the option to backup and restore Apps, Browser data, Google Keep data, etc.