When you're checking reeds, you want to note how much tension they have against the cage as well as physical damage.
Clean all of the oil off, then check tension...the oil can make the petals "stick" to the cage and act like they're being held down by tension.
Once it's clean, see if you can see daylight through any of the contact points or if they're at all loose.
If either is true, buy a new set of petals/reeds, they need to hold tight against the cage to provide a good seal and work properly.
You can lift the petals up with your fingernail and they should snap back in place.
If you notice that some make a dull snap or hardly anything at all, time to replace.

You can also take the plate that holds the petals on and look for deformities like you'd see in an old gasket that was over-tightened.
That's generally where the reeds lose their tension, right at the edge of the plate they'll form a groove.
If you see this on your reeds, it's probably time to buy a new set of petals (you don't actually have to buy the entire cage, you can simply replace the petals).

A good replacement reed cage to run would be the Vforce 2 or 3 (definitely the 2, some debate over the 3's), boyesons are a better reed than OEM, and I personally had excellent results with Boyeson's RAD valve.
I might catch some flak over the rad valve, but I used it on an 88+ cylinder along with a Q (at that time) 250 pipe and nothing else done to the engine to hit top speeds that some zillas never see.
They maintained their tension for probably 200hrs of my personal ride time, and they were used when I got them.
One of the best things about them was that they came with a nice aluminum intake boot with a thick rubber hose to mount the carb.
It smoothed out the intake tract considerably compared to a stock rubber boot.