The reason it matters at all is that a first year business has no institutional credibility, which means the person is the evidence. Somebody deciding whether to hire you is establishing whether you seem competent and whether they would want to deal with you, and a profile containing only announcements answers the first question badly and the second not at all.
What works is content that is adjacent rather than separate. Something you noticed while doing the work, an opinion about your industry, a book or a tool that changed how you approach something, or a straightforward observation about running a business. Those are personal in the sense that they come from you, and they remain relevant to why somebody would hire you.
What works less well is the genuinely unrelated, particularly at volume. A business account posting about weekend plans, holidays, and family occasions has become a personal account with a business name, and the audience that followed it for professional reasons stops paying attention. That is a different thing from the occasional glimpse.
The distinction that matters is whether it would make sense to say to a customer. Anything you would mention in a conversation while waiting for a meeting to start is fine. Anything you would not is probably not, and that test resolves most of the uncertainty without requiring a policy.
Avoid the categories that reliably cost you something. Politics, religion, and anything contested divides an audience you built for other reasons, and the people who disagree do not tell you they left. Complaints about customers, however anonymised, are visible to every current customer. And anything that reads as a grievance sets a tone that is difficult to recover from.
Be careful with manufactured vulnerability, which has become a recognisable genre and is widely disliked. A carefully constructed story about a setback that resolves into a lesson about your business reads as a technique, because it is one. Genuine and occasional beats structured and frequent.
Consider that consistency of voice matters more than the ratio. A profile that sounds like one person, whether it is discussing work or something adjacent, is coherent. One that alternates between corporate announcements and casual personal content reads as two accounts sharing a login.
Then judge it by whether the account still does its job, which is being findable, current, and credible to somebody checking you out. If somebody arriving from a search would conclude you are a competent business, the mix is working. If they would be uncertain what you do, it is not.
Keep a genuinely personal account separate if you want one, since that resolves most of the tension. A business profile can stay professional while you post whatever you like elsewhere, and conflating the two is what produces the discomfort.
Watch what actually receives engagement rather than assuming, since the answer is frequently surprising. The posts people respond to are usually the ones that felt least like marketing, and that pattern is worth noticing before deciding the mix by rule.
Remember that anything posted is permanent and screenshottable regardless of privacy settings or later deletion, which is worth holding in mind for anything you would be uncomfortable seeing quoted back.
Consider whether the platform is producing anything at all before optimising the content mix, since many local service businesses receive almost no enquiries from social regardless of what they post.
Set a rough proportion and stop deliberating about each post, since the deliberation costs more than the decision. Something like one adjacent post for every few about the work removes the question entirely.