I think Biblepay usese deterministic wallets so this does not apply. Rob, can you confirm this?
On walletbackups, the dash subsystem does create a copy of wallet.dat once per boot and copies this file into \backups. Something like mmddyyyy.dat.
I recommend keeping a copy of a good wallet offsite - maybe on a CD and USB flash if possible in a safe.
Anyway regarding the necessity to make constant backups: There is truth to both sides but let me explain this nuance.
It is true, that if you only have one plain vanilla address with all your BBP allocated to that address, no matter how big the physical wallet.dat file gets, you can always get back all your bbp, if you had a backup of that original small file somewhere. The wallet will expand in size as you resync the chain and you will gain all your BBP back.
The specific issue that requires you to back your wallet more often is this: If you *add* a receiving address to the wallet, it comes with 1000 keys, if you have been mining for a while, if the action of creating a new address (doing that creates a keypair - a private key and a public wallet address), if that resulted in creating a new keypair that was *not* in the original backup, *and* you send BBP from somewhere to that new address, now that part of your balance is *not* in the original wallet. Now you need a new backup.
So you either have to cognizently re-send your BBP periodically to your *original* address, and then you are fine, *or* keep backing it up.
Btw, an easy way to understand this is if you loop through your addresses and balances, if you were to type:
dumpprivkey publicbbpaddress
For each address with a balance, you could print those keys out to a printer and have a way to gain access to the BBP if you ever lost the cold wallet backup...
Its also beneficial to consolidate your wallet as the core will run faster, but it also risks a loss of privacy. The reason the devs made so many keys it to obfuscate your identity. If you dont care about anonymity, by all means send it all back to one address. If you do care about anonymity let it bloat and keep backing it up on a regular basis.