When the spreadsheet stops coping.

Buy, unless your process is genuinely different from what the product assumes, or you are paying heavily for features you never touch. Custom software earns its cost when the process is the competitive advantage. I would rather tell you that on the first call than eight weeks into a build.

It scales with the number of distinct processes, user roles and integrations — not with the number of screens. I scope a fixed price for a defined first version after a mapping session, so you are not signing an open-ended hourly commitment.

Yes, entirely, along with the database. It is delivered to your repository or your server, in your name. You can hand it to another developer at any point, and I will help with the handover rather than obstruct it.

PHP with MySQL for most business systems, which is deliberate rather than nostalgic: it runs on ordinary hosting, any competent developer in India can maintain it, and it does not tie you to one vendor. Where a project genuinely needs something else, I will say so.

It is the right question to ask a single developer, and the answer is documentation and conventional technology. The code is commented, the database is documented, and it is written in a stack that thousands of developers know. You are not buying a system only I can read.

Sometimes. It depends on whether the code is comprehensible and the database sane. I will review it and give you a straight assessment, including the case where the honest answer is that maintaining it will cost more than replacing it.