Question : Problem: Common backup procedures/standards

I've been hired as the network admin for this company and recently noticed their backup/recovery capabilites are horribly inadequate, so I'm getting started on the solution. Right now they are only performing backups once a month...with a capacity of about only 3 months.

I've never been the sole admin for disaster recovery so I'm asking for input:

I am going to set up daily incremental backups and weekly full backups...standard practice by most I would assume.  I also plan on doing a full backup once a month to keep 6 months (possibly more) worth of backups on retainer.

My question is, how long should I keep daily and weekly backups on file? I know this is arbitrary, but I'm looking for a "standard/good practice" type of answer.  Should I keep daily and weekly backups accessible for the full 6+ months? Or should I keep daily/weekly backups for..lets say one month, then keep 5+ months worth of backups on a monthly scale?

Just to reiterate, I'm looking for good standards and would like to hear what fellow experts think. Open discussion. Feel free to critique my plan and offer constructive suggestions. Thanks!

Answer : Problem: Common backup procedures/standards

What types of tapes are you using? How much space are your differential backups taking at the moment? Remember, a differential backup only backs up the changes since the last full backup, while incrementals backup the changes since the last backup. A full backup is usually taken every weekend, so the differentials or incrementals are done the other 4,5 or 6 days of the week, depending on your working days (normally 4 diff and 1 full backup would be the standard). In most cases an incremental backup will hardly scrape the beginning of a tape, and 4 incremental backups would be equal to the last differential backup you'd do during a week, and this would still fit snugly to the first half of the tape. So I don't think you'd need more tapes whether you backup differentials or incrementals. Also the time used would still fit easily.

Only if you have a huge number of changes done to your files every day would that be a problem.