Buy Beats Build
every time

Somewhere in central London, packed between a railway line, one of the capital's busiest roads and some of its hippest bars, clubs and restaurants, is a compact jumble of back-streets and warehouses. One of these is a hire shop for film equipment: cameras and lights, tripods and dollies, microphones, monitors and more. There are dozens of these hire shops around London. If you're shooting a film of any scale, from your film school graduation, to a documentary for Netflix or Prime, to the very biggest Hollywood blockbusters, these are where you find your equipment.
Yes the very biggest players in film and TV production do not own all their own camera, lighting and sound equipment.
It's simple economics. My London production company might shoot one, two, three projects in a year. That's not enough to justify buying a the kit. On top of the purchase price (and there's a lot to buy, for a whole lot of initial outlay) there's warehousing and upkeep. Who am I going to pay to maintain my fluid tripod head? How long must I keep my pricy digital camera once it's obsolete?
The hire shop on the other hand can rent out the kit week after week. A high end production needs a 35mm-equivalent digital camera while documentary needs a semi-pro camera on a limited budget. Done! Hell, they even have a camera from the '90s that shoots on real film1 if that's your thing. And as a production company, I outsource the maintenance and keep up-to-date with the the latest hardware.
The hire shop can achieve all this because by hiring out to production after production they achieve a utilisation that the production companies themselves cannot.
For film production, hire beats buy. Hands down.
From film hardware to business software
You're not a film production house2. You're in content publication or shipping or professional services or local government. One way or another we all use computer software daily, and sooner or later our business needs something specific. Something other than Microsoft 365. When does it make sense to build it ourselves (or hire a software company to do it for us) rather than buying it off the shelf?
Never.
If the software that we need exists for sale, and it's good enough for our purpose (not necessarily perfect) and we can afford to buy it, it is not cost effective to build it ourselves. If we build, as well as the initial outlay we take on all the warehousing and maintenance costs, analagous to a film production company owning their own camera. It makes no sense.
If the software that we need exists for sale, and we can't afford to buy it, it still makes no sense to build it. Building will always be more expensive than buying. Consider the maintenance costs alone. If it takes just one of our people only 2 or 3 days a month to maintain the software, that's easily a monthly £1000 cost to our business. No, if we can't afford to buy, we definitely can't afford to build.
If the software that we need exists for sale, and it's good enough for our purpose, we buy. Every time.
Eating our own apple sauce3
Sodium Skies is a software company. Obviously we're going to tell you to buy. How sincere are we really?
Well Simple Data System is a fairly sophisticated piece of software. By comparison building a web contact form is well within our reach. Now take a look at our Contact page. It doesn't look quite like the rest of our pages. The styling is definitely a bit different, and honestly it doesn't work quite the way we'd like (there's that obvious JavaScript loading state, and the link to the Privacy Policy could bear to be more obvious). And the page has another company's name near the bottom of the form. Because web contact forms are not our core business. And it's easily good enough. And it's definitely not worth the time to build and maintain it ourselves.
Because even for our own business – especially for our own business – we know that Buy Beats Build. Every time.