Well there is no "standard" per say as many sites have different
requirements and limitations. For instance if the site is 24x7 you may do
things differently than one that is 9 to 5. Here is a good document that
might help you decide. Although it is written for 2000 most still applies
for 2005 as well.
http://www.microsoft.com/technet/prodtechnol/sql/2000/maintain/sqlops0.mspx

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Andrew J. Kelly SQL MVP
Solid Quality Mentors
> Hi;
>
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> Rock