A day before yesterday, while deleting some duplicate contacts, my dad accidentally deleted all of his contacts. Backing up your contacts should be first thing, most of us should do, since you never know what might happen.
Thank God, I had taken backup of his contacts locally, so I was able to quickly import it in his contact app. Here are few tips, so that you don't forget to take a local backup of your contacts.
Use Nextcloud, it provides a great option to automatically backup your contacts everyday, it will do it's job, without you even knowing it. If you self host the service, then it's even better. The other way, is to set a reminder to remind to backup the .vcf file from your phone.
As someone who doesn't use google services, the above approach works perfectly for me. If you guys have any better solution, let me know.