Security deposits we collect are always equal to one month's rent. It's easy to remember that... no matter what property we are talking to a potential tenant about, it's going to be equal to one month's rent for the property being discussed..
Some people think it should be more, and some want it to be less. What we ask for is reasonable, and if someone can't come up with deposit it raises some concerns in the ability to pay rent each month.
When a security deposit is used or withheld, the amount is rarely close to one month's rent. If there is damage or cleaning that needs to be done, it's rarely significant with tenants we qualify and place. When we've seen situations (not our situations) where significant damage occurs, it's beyond anything that could have been collected as a security deposit up front. Tenants aren't going to pay $10,000 for a security deposit when rent is $2,000 per month.
The bottom line is doing a better job screening at the beginning eliminates many of the problems that can occur with security deposits.