When developing a script you are probably running it multiple times at the very least and for a large script it may be in the hundreds of times that you run it and test it. If the script is making changes to a database, such as creating fields, deleting fields, etc you might want to refresh your database every once in awhile. I have had several occasions (this morning was one of them) where I was working with a fairly large script, part of the script created a number of virtual fields in one of the database. So when I ran the script this morning and starting getting strange errors, such as not being able to save the view, that were not there when I ran the script last week. I decided to delete the database and start with a fresh copy and all the errors disappeared. It seems that if you make lots of changes the database header starts to become corrupted. Now I am currently doing this on V8.5 as the client hasn't upgraded to V9 yet so V9 could be fine but even so if you are doing lots of testing that entail changes to the database you might want to refresh your database on occasion.
