Question about filament life

Hi All, I am a newbie with a recently purchased Ender 3 Pro.
I added a glass bed and Capricorn tubing after purchase.
For several weeks it has worked just fine. I use only PLA.
Some days ago it started to fail early on in printing - just a mess of filament on the plate.
So I read the forums and did the following:
Replaced the hot end head (assumed blocked) and associated bowden tube
Double/triple checked the bed is level.
Used only default settings for several different prints.
Attached image is a failure example. Filament everywhere!!
Now, my question please:
Could this be due to filament being left exposed?
I have three reels of filament and they are not stored in a sealed dry container - just the original unsealed plastic bag with the original tiny silica gel sachet.
Purchased in July so stored for about 8/10 weeks. One reel left on the printer when not in use.
I have tried using two different filaments with the same results.
Is there any way to test/check if a filament reel has 'gone off'?
If it's too brittle, should it snap off by hand.
I am hoping the problems are due to bad filament. How might I know?
Any other comments appreciated.
3DM

It's probably not the filament. PLA doesn't go bad that quickly.

to be honest this seems to be a classic case of the print coming of the bed plate. Have you cleaned the surface recently.
Use acetone for preference.

essentialy getting the first layer right is 99% of 3d printing.

To be sure of a good layer:
1) calibrate the bed, then do it again - use 80-90gsm paper and it shoudl just slide between the nozzle and the bed with a little friction.
This is done with the manul levelling knobs and is VERY important. Any 'auto llevelling' devices do something completely different - so regardless of what 'auto level' system you have it is still crucial to actually physically level the bed.

2) print speed. To get a good first layer you need to print the first layer slowly. Often I use 10mm/s or slower. Now a lot depends on the actual print surface and filament.
But the general rule of thumb is that if you are having adhesion problems - slow the first layer down.

3) print surfaces. There are now a LOT of different print surfaces and they all have their positives and negatives. If you are having problems with a particular filament and surface combination - consider using a commercial print adhesive. Dimafix is thebest I've used. magigoo is also excellent.

4) most slicers will let you adjust the z-gap (distance between the nozzle and the bed). As long as your bed is LEVEL - see point 1 - this can really help get a print sticking. Sometimes you actually need to make the gap slightly larger and sometimes smaller. I tend to go up and down in 0.05mm increments.

So auto levelling - why is it a total waste of space ? (lol)
What it actually does is check if the bed is flat. Or if it's got depressions and bumpd. It then maps the bumps and hollows and moves things up and down while printing.
However if you do have an uneven bad - the best solution is to get a bed that is properly flat.
If you have a flat bed, you do not need auto levelling.

what do you use to the bed prior to printing? and spray, or stick glue? I use purple stick glue. After about 4-5 prints , theres a buildup of old glue nothing sticks. So I clean my be with windex, a razor blade, and paper towels then my glass bed is good as new.