Identity Key possible problem

Has anyone experience any problems with identity key value not incrementing properly? I have a table with an identity key which should increment by one but has missing value. I would just like to exclude the possiblity of a SQL Server error.

Missing values happen for identity columns when transactions are rolled back.

Each time when you do an insert, the identity value gets incremented, but if the transaction that contains the insert does a rollback, you will loose the value.

You are guaranteed that you will never get the same identity value, but it is possible to get holes in the numbers.