Bank Accounts

So, my husband and I have been transferring money from our paycheck to a saving account to hold money for upcoming bills. I'm wondering if its a good way to do it or if there's a better way. For example - my husband's truck is ~$400/month, so we divide that by 4 (he gets paid weekly) so every paycheck $100 comes out of his paycheck and goes into savings until the bill is due.

We don't do this with all of our bills but maybe we should? We only do this with rent and car payments.