Dallas, I’ve never had an issue. Houston, I got all kinds of zits and pilling and was thinking about getting or making a filament dryer before we moved. Both can be pretty humid, but the difference between 60% and 90% is significant.

25%. My dehumidifier doesn’t go lower than that.

I live amidst the great lakes. I took great care with bagging and sealing and drying when I was using Creality printers, because it really mattered. I’ve been lazy about it since ditching them, and my Centauri Carbon could not give a shit. I could leave filament on my lawn and this thing would just chew right through it.

I have humidity sensors in both my dryboxes and outside.

Where I live humidity in summer is 40-60% and the dryboxes will max out at 40% if left untouched.

In winter it’s 20-30%.

Petg starts having issues at 30 and you can hear the water boiling at 40

Southern Norway is quite good for keeping stuff in the open.
Around 35% now, peaked at mid 50s in summer and much lower in winter.

Never really need to dry PLA/PETG, but TPU does need it.

I do run both AMS every once in a while, mostly to regenerate the silica tubs a bit.

I did have stringing on PETG once, but drying while printing was enough to solve it.

In northern Minnesota the humidity can vary greatly. Last weekend it was 90+% outside. While indoors the air conditioning had the house around 50%. And by winter time, the outdoor humidity can be as low 20% and indoors depending on heat source, around 30% to 40%.

I finally broke down and bought a dedicated filament dryer, Sunlu S2, because my trusty old food dehydrator died the week before. I do dry PETG when it tells me to, and I always dry TPU. But never PLA.

Just for fun, after I was done drying and printing some PETG, I dropped a mostly used spool of Sunlu white PLA into the dryer, (first time ever for PLA). That spool has been laying around in the open for at least 6 months now. The humidistat on the dryer showed 30%. I let it dry down to 20% and ran a test cube. No difference in print quality that I can see.

I have a spool of PLA that’s been sitting out for a year in 30-80% humidity and it printed up just fine, I didn’t even dust it off.

I have about 50% humidity and don’t usually dry my filament and I start to have issues with the outer layer of the spool snapping repeatedly when feeding after a year or two of sitting out. I used to have a dryer for cases like this but it got left behind in a move so I currently try to only use my new spools until I can get another one because I don’t trust using the oven and using the heat bed is really slow.

I’m of the general opinion that the hullabaloo about drying filament is largely not warranted in most cases. PLA is just not very hygroscopic and can sit out for months without any issues. Even PETG I don’t have any issues with it sitting out. The room I print in sits at about 50% humidity most of the time.

I keep most of my filaments in a box with dessicant that I bake maybe once a year, but I’m not convinced it is really doing much. The only reason I have a drier is that I started printing occasionally with materials that are much more hygroscopic (e.g. TPU).

The humidity here varies between 3% and 100%.

Things change from PLA being regenerated by being left open to it not lasting for two weeks before it needs drying.

Unless you live somewhere where it’s always close to that low in my interval, I do strongly recommend a drybox to anybody wondering if they need one. At 60% humidity, PLA already visibly degrades way faster than you will use in a hobby.

Also, in my experience, filament driers only help with close to dry filaments. The temperature you would need to really dry them is larger than the glass point of most plastics. Microwaves work better (I guess because they heat the water in an uneven way) but it’s still hard to regenerate very moist filaments.

Right now, around 50% RH indoors. I leave my spools of PLA on the printer for months or even years, and I’ve never had any humidity issues. If I were to speculate, my guess would be differences in additives being the main reason that only some people need to dry their PLA filament.