Upload schedules are important. They allow your fans and subscribers to plan their week around your content specifically, rather than you having to hope that your video isn't yet buried under their other subscriptions once they do look into their subscription feed - if they do that, at all.
There are a couple different strategies for how often you should upload, but first, let's look at the stats.
On average (over the latest 20 videos) out of the top 100 channels (by subscriber count):
29.5% upload at least one video per day
40.2% upload at least one video every other day
49.8% upload at least two videos a week
61.2% upload at least one video a week
83.2% upload at least one video a month
All upload at least one video once every 145 days.
Uploading one or more videos a day is a thing that you can do if you have fast-to-produce or live content, or a team that can produce lots of content. Doing so has benefits:
It maximizes the chance that your video will show up first once a subscriber looks into their feed
If you also upload your videos during the same time period (eg the afternoons), people can plan their day around your videos like "after work/school, I'll watch X's new video"
It allows you to do time-sensitive topics most of the time. Even if you're pre-producing and publishing from a backlog, throwing in a recent thing always is possible.
It lets viewers use your channel like they would use a TV channel, ie as a thing they can have running more or less the entire period of the day where they would have a TV running otherwise. If a lot of your viewers do that, it opens your channel to a degree of freedom where you can have various, rather different shows running.
It however has drawbacks:
It's difficult to sustain. Especially as a lone all-in-one creator, you'll likely succumb to either burnout, or to a state where you are continuously grind out videos without actually having time to think about if what you're doing is good or how you could improve. This can lead to a general circle of unhappiness where your channel isn't moving forward even though you're trying your hardest.
If you upload too many videos a day, especially if it's in relatively different formats or about different topics, you may cause viewers to unsubscribe because they no longer want to get "spammed" by your videos.
Uploading every other day, a couple times a week or just once a week
Uploading on a weekly schedule has almost the same benefits as uploading daily, but is a lot more sustainable. This is the safest way to go if you are making content.
If you are approaching this schedule, it's very useful to tie specific days of the week to different formats. Even if you want to make a video every other day, you typically have a much easier time getting your viewers to watch their videos if they know "every monday/wednesday/friday after work/school I can sit down and watch X's new video"
Uploading fortnightly, monthly or rarer
If your video needs more time to be produced, uploading fortnightly or monthly may seem like the only option. Compared to the aforementioned schedules, it has the major drawback that viewers can't really plan for your videos. Choosing to upload on certain dates on the month (eg the 13th of the month, or the second sunday) can help here a little bit, but it takes a dedicated fan to keep track of a relatively minor event like an upcoming video upload for as long as a month.
If you upload even less frequently than monthly, another thing can happen: People subscribe to channels they like and unsubscribe from channels they no longer care about. But before they unsubscribe, they typically spend a long time just ignoring videos showing up from the channel in the subscription feed. If you upload very rarely, it can happen that by the time you upload your next video, people will already have forgotten who you are and what made your videos so enjoyable to watch.
This is (one of the reasons) why high-quality educational aren't that successful on YouTube and one that TV knows how to avoid:
TV shows rarely run less frequently than weekly, even well-produced ones. It's true that this is partially because they have a budget on which they can operate, but also because they use seasons. With seasons, you can output high-quality content on a weekly basis, reap all the benefits thereof and end the season with not only new subscribers, but with a bunch of new fans that you have taught that your channel brings high-quality content, a bit like a language teacher teaches children to remember words by repeating them. Unlike with just a single video the viewer happened to stumble upon and subscribed, this taught knowledge sticks much better, and once the new season begins a year later, the a lot of fans will drop whatever they were doing to watch your videos.
Uploading in seasons also solves the problems of "when to advertise your channel" (just before the season starts) and "when to find time to re-evaluate and adjust the format" (after the current season ends) and is for example how the channel Epic Rap Battles works. This to some extend also is how professional music channels work, although for those they typically don't have the problem of keeping people watching (favourite songs tend to get listened to again), plus they typically have the seasons in reverse: They upload videos whenever they release a new album and expect to go on tour with it soon and during the time where they don't upload they actually make money with concert tickets.
Unlike TV, you can also have a filler format/BTS show for the off-season so you can output some easier-to-make fanservice, however, also unlike TV, you'll likely face difficulties finding a budget large enough to survive the off-season. So, this is something you should try looking into if monthly options would be your alternative.