The instinct is to choose based on where the audience is largest, and that is the wrong criterion when you can only sustain one. A platform with fewer of your customers where you will post consistently beats a larger one you will abandon in two months, because the value comes entirely from accumulation and a dormant profile is worse than no profile.
Match the platform to what you actually have to show. If your work is visual, a visual platform is doing half the job for you. If your value is explanation and expertise, a text based platform lets you demonstrate it. If you sell to other businesses, the professional network is where those people are in a working frame of mind rather than a personal one. Businesses fighting their own format, posting text on a visual platform or attempting photographs of intangible work, produce content that is difficult to make and performs poorly.
Consider what the platform is actually for in the buying process, because they do different jobs. Some function as discovery, where people encounter businesses they had not heard of. Others function as verification, where somebody who already has your name checks whether you are real and active. A first year business frequently needs the second more than the first, and the verification job is satisfied by a modest, current, credible profile rather than by volume.
Be honest about what you will sustain. Twice a month, held for two years, outperforms daily for six weeks, and the calculation should be made against your busiest month rather than a quiet one. Most abandoned business accounts were started with a frequency that felt achievable during a planning session.
Claim your name on the other platforms even if you do not use them, which takes an afternoon and prevents somebody else taking it. Leave a current description and a link to your website, and nothing else. A profile that clearly exists as a placeholder is fine. One that appears to be an active account and has not been touched in a year is not.
Then measure whether it produces anything before increasing the effort. Ask new customers whether they saw you there, and watch whether posts produce messages rather than reactions. A meaningful number of small businesses discover that social contributes almost nothing to acquisition while consuming several hours a week, and the honest response to that finding is to reduce the commitment rather than to work harder at it.
The alternative worth considering is that for many local service businesses the answer is none of them. A complete business profile, a steady flow of reviews, and a site that answers the questions people ask will outperform a social account maintained reluctantly, and choosing that deliberately is a legitimate strategy rather than an omission.
Set a review date when you start rather than continuing by default. Six months is enough to know whether anything is happening, and deciding in advance what would justify continuing prevents the common outcome of maintaining an account for years because stopping would feel like an admission.
Repurpose rather than producing separately, because the effort is what makes this unsustainable. Anything you write for your site, any photograph taken during work, and any question a customer asked is material for a post, and treating social as a distribution channel for work you were doing anyway is considerably more durable than treating it as a production requirement.