Erin Stellato has put together a set of scripts to collect baseline stats for an instance:
The topic of baselines in SQL Server is one that I’ve had an interest in for a long time. In fact, the very first session I ever gave back in 2011 was on baselines. I still believe they are incredibly important, and most of the data I capture is still the same, but I have tweaked a couple things over the years. I’m in the process of creating a set of baseline scripts that folks can use to automate the capture of this information, in the event that they do not have/cannot afford a third-party monitoring tool (note, a monitoring tool such as SQL Sentry’s Performance Advisor can make life WAY easier, but I know that not every can justify the need to management). For now, I’m starting with links to all relevant posts and then I’ll update this post once I have everything finalized.
If you don’t know what “normal” looks like, you’ll have a hard time discerning whether something is wrong. The better you understand a normal workload, the easier it is to spot issues before end users call you up.