Hiring in-house gives you the most control. The people internalise your customers and your data model over months and years, and this context stays with you. The cost is time and rigidity: filling a senior role takes months, ramping up adds more time, and custom software vs saas the salary continues through the quiet quarters.
Full outsourcing means the vendor owns delivery: they staff the team, they manage the day-to-day work, and the provider carries the delivery risk. The model works when the work is a defined project and there is a decision maker with time for it. It works badly when nobody on your side owns the product, since a vendor is not able to invent your business rules.
Hiring individual contractors which is better php or python the middle option: you rent capacity while keeping the planning and the management yourself. The main advantage is speed — a suitable engineer is often available in weeks rather than months — and the commitment ends when the work does. The catch remains that your technical leaders have to have the capacity to direct the work. Without strong internal leadership, you are paying for effort with no owner.
In the real world, these models are combined. One durable pattern puts architecture, product decisions and core domain code with permanent staff, while an outside vendor handles the parts that are bounded and specifiable. The rule holds: retain the parts that are hard to re-learn, and outsource anything a competent team can specify and deliver.
Three simple questions usually settle it. To begin with: is this software central to how you make money, or internal plumbing? Second: for how long will the work last — months or years? Third: who will maintain it in two years? Work through them with real answers and the right arrangement is normally clear.