the private key is the most important thing to make access to a wallet and once lost is almost impossible to recover again unless backup or wallet service provided a recovery phrase which we backup in this situation offline backup of each one would ensure totally in safety is the wallet since you would be in control of the coins without anyone esle access for it .and in other words its a good idea to keep the wallet in mind because when it's gone its hard to really come back so double the be care and keep more than anything .