Correct. The cost of time is huge anyway to do anything properly.
I think the key with any large chunk of work is knowing what you're shooting for.
I've gotten bogged down in bug fixing, there are modules that do the brunt of the work but nothing that works as you want out-of-the-box. Then again I want a near-universal backtester with a GUI (but without complex position management).
Obviously something without a frontend is much easier and requires much less time.
True but better to take longer than finding nothing because one would be forced to test and analyze data the same way the original architect did. That can often greatly limit artistic freedom and understanding of details. Am not talking about writing a comprehensive algo trading platform but designing one's own profiling and test architecture to try out ideas. I find that incredibly important and valuable.
It is valuable absolutely. The option to implement any feature in days vs being tied to some commercial software which might get unsupported on a whim, there's no comparison.
Take Amibroker or MultiCharts, if there's ownership change and say you're relying on CQG data and IB for trading - they can modify their APIs, software authors decide to discontinue support (has happened before) and that's really the end of line. You're out of options.
But a simple backtester and a comprehensive one are two radically different sized projects.