First of all, what is cross posting?
Simply put, cross posting is when you make one post, and share it across multiple platforms. For example, you post a a picture on facebook, and it automatically posts on instagram and twitter, too.
What are the benefits?
It can definitely make life easier, since you don't have to go on multiple sites and upload it all separate times. If you are trying to promote an event, being able to share it all instantly can be a real time saver.
What are the drawbacks?
Well, for one thing, what looks good on facebook doesn't always look good on instagram or twitter. They all have different default sizes for displaying images, for example. so that graphic you posted on facebook might have important text or images cut off.
Another issue is that some of your audience will follow your brand many platforms. If they keep seeing the same exact post from you everywhere, they'll likely get audience fatigue, and just stop engaging.
Yet, it can be even worse if your audience is different - instead of seeing the same post they've seen before, they just see a badly formatted post once.
So, should I cross post?
Short Answer: no. Athena Content Creation likes to use cross promotion tactics as opposed to just posting the same thing on every platform at the same time. We create different graphics and posts for each social media page - but we still make sure they are all fairly similar in branding and style. This helps brand cohesion, and even better, your audience won't get tired of seeing the same thing over and over.
I would reccomend using cross promotion instead of cross posting as much as you possibly can. Social media can be hard to manage correctly, but as long as you follow the same rules for all of them, you'll be set: Be genuine, post high quality content, and care about what you're trying to say.