I think that's a bit too open ended of a question. How much drive space is available to be allocated? What is the database used for (OLTP or OLAP)? Are there any bulk load processes that import lots of data at one time or are the transactions spread out smoothly over time? Is this a database that you monitor constantly, or is it a remote (client) database that you only get to see once every three months?
For the most part, I will let SQL auto-grow itself up until a db gets to about 20 GB (or 70% of available drive space); after that I take over and schedule db growths manually. Obviously, if a db runs the risk of auto-growing outside the bounds of its available disk space, then I will take over then as well.
Try to always set upper growth bounds on the data files and the log files; nothing worse than a log file that has run wild all over your remaining free disk space (well, okay, there are lots of things that ARE worse, but this is a preventable situation).
How much free space you have actually within a database is more a function of how much you want to intervene and how much you want the db to operate on its own. Where I work now, I have a 200 GB db. I try to schedule db growths during our monthly maintenance windows, so I always try to have enough free space to make it at least to the next window. Usually I end up adding enough to make it through at least two months.
Originally Posted by milan1115
Have you hugged your backup today?