Can't live with 'em…can't live without 'em.
Damned if you do…damned if you don't.
Very few people like change, especially in corporate environments. It's just another burden to bear. If something's changing, you know what'll follow; a meeting, memo, or training. Who wants that?
Rolling out a retention policy will usually result in a lot of complaining, but when coupled with all of the complex, new eDiscovery regulations, it gives you something else to worry about – even if you have no anticipated litigation at the time the policy is implemented (notice I didn't say 'pending', which isn't the proper standard).
Just ask CalPERS, aka the California Public Employees' Retirement System. CalPERS implemented an internal 60-day retention policy – and apparently didn't bother to tell anyone. Furthermore, they gave 2,300 of their employees discretion over what additional ESI should – and shouldn't – be kept.
Oh, did I mention they're currently under state and federal investigation?
It's prudent to be aware that, no matter when a retention policy is implented, your opponents will always have an interest in claiming you're committing misconduct by deleting evidence of…misconduct. Therefore, I rountinely suggest that, prior to implementing – or modifying – a retention policy, a thorough review of current status should be performed – just in case you have to explain it to the judge.