Customized software development services is the broadest label in the market and covers work varying enormously in difficulty and price. Making proposals comparable is mostly a matter of forcing every bidder to be specific about the same small number of things.
The six questions that make proposals comparable
Which platforms. Whether a backend exists or must be built. How many user roles and what each can see. Which external systems are integrated and who owns credentials. Whether designs are provided or produced. And what is explicitly out of scope. Proposals answering those six stop resembling each other, and most apparent price differences turn out to be scope differences rather than value differences.
When desktop beats the browser
Sustained local computation where shipping data to a server is impractical, deep operating system integration such as file associations or background services, hardware access beyond what browsers permit, very large local files, and genuine offline operation in places without reliable connectivity. If your requirement is not on that list, a browser application is cheaper to build and dramatically cheaper to distribute and update.
Desktop shifts responsibilities onto you
Desktop software has to be distributed, signed, updated and supported across operating system versions you would rather not carry, and it runs outside a browser sandbox so the security burden is yours. Scrutinise the update channel hardest, because compromising it compromises every installation, and ask how a failed update is recovered. The NIST Cybersecurity Framework is a reasonable structure for that whole conversation.
Price the years after launch, and keep the exit
Require an annual figure for dependency and security updates, platform compatibility and hosting alongside the build price. Require repository, pipeline and accounts in your name, documentation in your repository, and an express written copyright assignment, since under 17 USC 101 commissioned software is not automatically a work made for hire. Those turn a supplier change into a quarter of work rather than a rebuild.
Questions people ask about customized software development services
How do we make customised software proposals comparable?
Force all of them onto six axes: platforms, whether the backend exists, roles and visibility, integrations and credential ownership, who produces designs, and what is explicitly out of scope.
When should we build a desktop application?
Sustained local computation, deep operating system integration, hardware access beyond browser limits, very large local files, or genuine offline operation. Otherwise a browser application is cheaper to build and far cheaper to distribute.
What extra responsibilities does desktop bring?
Distribution, code signing, a trustworthy update channel, support across old operating systems, and security outside a browser sandbox. Scrutinise the update channel hardest, since compromising it compromises every installation.