At our office, we have nice coffee makers and unlimited Starbucks coffee beans. The problem is, I'm just not sure when the coffee was brewed. Was it brewed yesterday? A few hours ago? Do I have to empty the pot and brew a fresh one? What is the proper procedure here?
I my office we attached a very small whiteboard and pen to the wall beside the coffee pot. Whenever anyone starts a brew they write the time on the whiteboard. Then it is easy to know how fresh the coffee. It is at everyone's discretion whether they drink old coffee or throw it out and start a new pot. The only rule we have is that if you empty the pot you start a new one. We work regular office hours and make coffee often enough to know that "9:30" this morning and not yesterday.
You could start even simpler than this. A stack of post-it notes and a pen could work. You don't even need to put up rules. Simply stick a note on the coffee machine with the time you made the coffee. Others will probably follow your lead.
If it's a bean-to-cup machine, then it's mostly freshly ground and brewed.
We have these at my office.
Basically, for fresh brewed coffee, you're looking for crema - the fine foam that you get on top of black coffee that's a light tan colour.
When I get my coffee, I check for this. If it's just flat black water, I'll tip it away and get a fresh cup out of the machine and I'll invariably get the crema on the second cup.
If you get latte or cappuccino out of the machine, then think again about what you're doing with your life - the milk in these machines is invariably dried powder and therefore pretty nasty (if you like coffee). Avoid this, if you value the taste of your coffee.
If you have a filter machine that dispenses into the carafe, then take a look at the filter (if you can) - are those grounds still warm and moist? If you can't get to the filter, just take the carafe away and give the machine a good sniff - does it smell of freshly brewed coffee?
Also, think carefully before you throw away a nearly full carafe of coffee, people might see this as being wasteful.
If in doubt, go with the taste. If you're happy, drink it - if it tastes of warm black water, throw it away and brew some more.