You can run most of your brand day to day without a designer. What you cannot do without one is create the thing you are keeping consistent in the first place, or fix it once it drifts. So the honest split is this: a designer builds the system and the pieces that set the direction, and your team runs the everyday output inside it. Get that division wrong in either direction and you either overpay or slowly go off brand.
Here is what a team can genuinely handle alone, once the system exists: the weekly social posts, the slides, the email headers, the small things you make constantly. That works because someone already made the decisions that matter and handed you templates to fill in. A lightweight brand system is the handful of fixed choices that make it safe: your logo in the formats you use, two or three colours with exact values, one or two fonts and where to get them, and real templates for the things you ship every week, all in one place the team can open.
Here is where doing it yourself quietly costs you. The system itself is not a DIY job. Pulling colours off your old site and picking a font that feels nice is how brands end up looking like everyone else, because the choices that make an identity yours are exactly the ones that are hard to make well. The same goes for anything that becomes the reference everyone copies: get the master template wrong and every asset built on it is wrong too, at scale, for a year. That is the work worth paying for, because it is the work that is expensive to get wrong.
So bring in a designer for the decisions, not the volume. The identity, the template system, a launch that has to land, a rebrand, the moment you outgrow the look you started with. These set the direction everything else follows. If you are paying a designer to resize the same banner every week, you have a system problem. If you are inventing your own identity from a blank page to save the fee, you have the opposite problem, and it usually shows.
Even with a good system, brands slip off course quietly: a slightly wrong blue, a downloaded font, a photo stretched out of shape. Keep one source of truth for the assets so nobody rebuilds from memory, and have someone review the templates every few months. But be clear about what that maintenance cannot do. It keeps you consistent, it does not make you better, and it will not tell you when the whole look has aged out. That judgement is why you keep a studio's number.
So run the day to day yourself, and do not apologise for it. Just know the line. The output is yours to make. The system underneath it, and the calls that reshape it, are worth a studio. If your brand is starting to feel improvised, or you are about to build the templates the rest of the company will copy from, that is not a job for your most junior hire. That is the part we would want to get right with you.