<p>I was noticing on a print I had just done that the quality was not up to typical snuff. I had just started using a roll of PLA filament that I had been keeping on a shelf without a wrapper for a couple months. How long can you store filament before it gets too hydrated from the air to print? I expected more than a couple months but perhaps I am wrong?</p>

In
theory
, most filaments don't go bad within a year. However, praxis shows, that averse conditions can impact the filaments over time and age them to unusability.
Among the damaging factors is heat, but most filaments also are hygroscopic and absorb water to some small degree, or even heavily like Nylon.
As a result, it always a good idea to at least try to store filament dry. To enforce this, some use racks in a well-heated room, others are blessed with very dry weather overall. And on some locations, like the coast, you might even be forced to use dryboxes for each and every filament to try to slow the degradation of steady hot humid air leaching out the additions from the filament.
Dryboxes can keep the filament reasonably isolated from the surrounding air and so prevent moisture interacting with them to some degree. It is also a good idea to store them out of direct sunlight, as UV light might destroy color and/or the plastic. More information on why to use them is for example at
this question
A couple construction videos using an IKEA box and a bit of foam were offered by
Tom (Thomas Sanladerer)
and
CNC Kitchen (Stefan Hermann)
in 2017.
But fear not: most filaments - PLA included - can be freshened up again if the damage is not to prolonged! Baking them at a low temperature or storing them in a dehumidifier has worked in some climates. For PLA, keep the temperature at below 80°C. A couple of hours should get some the moisture that has seeped in out again. The Quality might not get back to that of fresh filament in all cases, but you might at least regain reasonable to good printability.
Also note, that different filaments are differently affected.
ABS for example is a little less hygroscopic than PLA, while HIPS is one of the least hygroscopic filaments available.