I build both WordPress and custom-coded websites, so I have no side to sell. Here is the honest comparison I give clients in consultations.
Choose WordPress when…
Your site is mainly content — pages, blog, gallery, forms. You want to edit everything yourself with a familiar editor. Your budget is tighter and timeline shorter. Roughly half of all business websites fit here, and pretending they need custom code just inflates the bill.
Choose custom development when…
Your website is the business process: bookings with rules, member areas, dashboards, calculators, unusual eCommerce flows. When plugins start fighting each other to approximate what you need, custom code becomes cheaper over time, not more expensive. Custom sites also carry no plugin-update treadmill and a smaller attack surface.
The mistakes I see
Mistake one: forcing WordPress to be an app with fifteen plugins — fragile, slow, hacked within a year. Mistake two: paying custom-development prices for a five-page brochure site. Mistake three: choosing based on what the vendor sells rather than what the project needs — agencies that only do one thing recommend only that thing.
The one-question test
Describe your website's job in one sentence. If the sentence is about showing things, WordPress is probably enough. If it is about doing things — calculating, booking, managing, matching — talk to someone about custom development. And if you are unsure, that conversation is exactly what a free consultation is for.