It's not really an issue of killing the number of write cycles on the drive, but there are some performance issues with current generation SSDs where you would want to keep writes/re-writes to a minimum.
The deal is this, when you delete data from a hard disk the data isn't actually deleted. The entry is just deleted from the file allocation table (or your filesystem's equivalent) and the space is made available. The data still resides on those sectors, which is why undelete utilities work. That's not really an issue on mechanical hard disks because when the disk needs to write to a free sector that has old data on it it can just overwrite the data. However, on an SSD it has to erase the old data first, then write the new data. The erasure of the old data takes longer than writing new data to blank cells would, so if you have a disk that has been heavily used you will see write performance going down considerably.
That being said, the newer generations of SSDs will include support for a command called TRIM that eliminates this issue. Windows 7 supposedly supports TRIM now, if you have an SSD that supports it. If you don't have a disk that supports TRIM (and very few SSDs do at the moment) then there's a chance that your SSD manufacturer may release a new version of the drive firmware that does support TRIM. They also may release cleanup utilities (OCZ has one for their Vertex drives called Wiper) that you can occasionally run to erase old data from cells to free up performance. There's also another feature that they are incorporating into some of their drives' firmware called Idle Garbage Collection, which basically runs a process similar to Wiper within the drive's firmware when your system is idle for extended periods.
So in summary, while your SSD may be rocket fast when it's new, the longer that you use it the slower it will because unless you are using TRIM or some tool that provides TRIM-like functionality on the drive. It pays to do your research. Right now I think that the OCZ Vertex is by far the leader in this area due to their support via Wiper, Idle Garbage Collection, and coming soon with TRIM support.
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CompTIA A+, Network+, Server+, Security+
MCTS:Windows 7
MCTS:Hyper-V
MCTS:System Center Virtual Machine Manager
MCSE:Security 2003
MCITP:Enterprise Administrator