In addition to temp & humidity, there's day length & ray strength to consider also. Shorter days make some plants grow more slowly, while other plants see an opportunity to bloom. Some of my plants seem to do more while inside for winter than outside for summer. A lot of that could be due to the high temps here, me putting them in too much light, I'm not really sure in every case.

It's not possible to just say yes or no as a generally correct statement, and I'm sure you wouldn't want to harm one that's not as much like the others as you think. Do you want to list your plants? You could get opinions about each.

No I would NOT care for the plants (broadly speaking) as if it's always Spring/Summer.

Day/night length is a definite factor. I'm quite comfortable making this as a general statement for most plants; I believe it's unlikely to go wrong here.

I too grow indoors only & I definitely water most things less in Winter than in Summer. There a few that I don't do that for, but I know which are more Winter growers (like Jades & my Haworthias) for which I should do that.

Am guessing that by 'ray strength' Purple means the strength of sunshine differing from warm months to cool months. That too is a factor. I have many plants on my windowsills, same exposure, but differing amounts of direct sun from Season to Season, noticeably different.

I'm guessing that as you become a more experienced grower, these differences, even if sometimes subtle, will become more apparent to you.

Good question, one we don't see often. Good growing to you!

Hi
Since most "houseplants" are of tropical origin because they are adapted to a lack of seasons, though almost all
tropical areas undergo distinct "seasons".mostly by the amount of water since the day length ,intensity, temps remain the same . I think a good general rule is, growth, .If growing, more water less if not Works for me lol
Most houses are maintained in tropical dry forest conditions so not so surprising that those are the type of plants that do well?? gary

I'll emphasize what the others have said by telling you that the influence outdoor light has on your indoor plants is far more important than humidity or even temperature..

Ultra Violet. I'd like to add, 'most' instructions are generic.
Like you mentioned, there's two basic directions.
Fertilize every two weeks in spring/summer and once a month in fall/winter.

Did you find instructions in a plant book or label on pot?
Plants have different fertilizer needs.
For instance, I do not fertilize succulents during winter. In fact, I don't fertilize any plant during the darkest months of winter.
In late Jan early Feb, 'depending on sun,' some plants 'Geraniums, Passionvine' get .25 dose.
See what I mean?
A rule not written on fertilizer labels. :)

I agree, although temp and humidity play a key role, sun is most important. Toni