An in-house team gives you the most control. The developers learn your domain over months and years, and that accumulated context remains with you. The cost is slow hiring and vertical software development services fixed overhead: recruiting a strong engineer is slow, onboarding adds several more weeks, and the payroll carries on regardless of workload.
Full outsourcing is the arrangement where someone else is accountable for shipping: the partner staffs the roles, they manage the day-to-day work, rust development agency and they absorb the risk of missing the date. This works well when the scope is reasonably clear and your side has an available product owner. It fails when there is no one to answer questions, because a vendor is not able to guess what the business wants.
Hiring individual contractors is the middle option: you rent capacity and keep the planning and the management in-house. It moves quickly — a matching profile is often available far sooner than a new hire — and microservices vs monolith it winds down as quickly as it ramped up. The condition is that your own leads must have time for code review and planning. If that capacity is missing, the result is paying hourly for uncoordinated work.
In the real world, companies blend them. A frequent arrangement holds the architecture and the core domain with permanent staff, while an outside vendor covers peaks, well-defined modules or platform work. The rule is simple enough: retain what defines your product, and delegate anything a competent team can specify and deliver.
Three simple questions resolve most of these debates. To begin with: is what you are building central to how you make money, or a cost centre? Next: for how long will you need this capacity — months or years? Last: who will maintain it in two years? Answer those honestly and the appropriate option is normally clear.