Software
Build an app when you need device capabilities a browser cannot reach and people will use it often enough to justify installing it. Both conditions have to hold; either alone produces an app nobody opens.
If none applies, a responsive web application does the same job without an install step.
Installing is a real barrier, and an icon on a home screen has to earn its place. Weekly use justifies it; occasional use does not, and 'our customers would download it' is an assumption worth testing with a web version first.
The wrong reason is presence.
An app because competitors have one, or because it signals seriousness, produces a permanent maintenance obligation and a listing with no downloads, which signals the opposite.
Often. It covers offline use and home-screen installation without store distribution, which handles a good share of cases where an app seemed necessary, though platform support for some capabilities still varies.
Two platforms to maintain, store review on each release, annual operating system changes that break things, and support for people on old versions. It is a permanent obligation, not a project.
Build an app when you need device capabilities a browser cannot reach and people will use it often enough to justify installing it. Both conditions have to hold; either alone produces an app nobody opens.
You have read what we think. If you want to know what it means for your case specifically, describe it and we will tell you which parts of when to build a mobile app actually apply — and which do not.
