Get your vitamin D checked, if you’re spending more than 30% of your time indoors, Which probably accounts for most people here, your vitamin D is deficient. Anything below 50 should be alarming.
Just to add to this, hydroxy-25 levels alone are not enough. Hopefully everyone's doctor also advises them what is a normal level for a healthy person and understands that people that are obese or have insulin resistance will deplete D3, C and Zinc faster due to the heavy load on their innate immune system dealing with low grade inflammation.
Anedocte: after I gave up folling recomendations from doctors that were happy after I just got from 17 to barely 25, I kept taking vitamin D and I'm aiming at 50. Asthma, severe allergic reactions (due to auto-immune), overall better hormone levels...
Doesn't it depend on what you eat too though? I'm inside a lot but also consume daily lots of stuff that contains high daily value of Vitamin D.