There are three ways to get capacity: you can buy it, rent it or build it.
If I buy it, I pay someone else to do it because I don’t want to deal with it. It’s a long term commitment and usually, I’m not looking to ever do the thing myself. Outsourcing.
If I rent it, it’s temporary. I’m paying someone else for a period of time, at which point I plan to do it myself. Contractors.
If I build it, I have to teach someone, coach them, train them. Employee.
If you’re going to buy it, do so because you prefer to pay someone rather than do that task yourself. If you’re going to rent it, do so because you need to fill a temporary gap. If you’re going to build it, do so because you know that in the long run, your business will be stronger and not reliant on outside sources.