In general a large table which had inserts and deletes causes fragmentation and poor performance. De-fragmentation on a regular basis should help there. Depending on how your reports are configured, partitioning might be a good idea.
thanks a lot for your quick reply. I saw those recommendations already, unfortunately they don't say whether or not partitioning is free of risk for this table. Customer says automatic defragmentation is not an option at the moment, that's why they're thinking automatic partitions which can be dropped easily would be an option with low effort. Reporting is not an issue and the partition key would be a datetime column anyway, so that the db optimizer can even benefit from the partitions.
I'd just feel a bit more comfortable if I knew that somebody has done this already and didn't encounter any problems with it.