in a minute
Startup tip #3:
a very common practice in the industry is to ask developers to estimate time and cost of a project based on just a list of features. this is a very bad idea because a text list doesn't explain how each feature works in detail and many unwritten conditions.
lets take the example of a loyalty points system. what are the rules surrounding the award of points. would the admin be able to change the rules whenever they want? are rules based on spending amount and tiers? what can users do with the points earned. can they redeem gifts or offset their bill? .
this is just the tip of the iceberg. without a clear idea of the user flow, asking developers for estimates is unrealistic (even with your own in-house team) as they'd have to fill in lots of blanks with their imagination. whenever anything is left to imagination, there will inevitably be a mismatch of expectations, rework, delays and unnecessary stress for all parties involved. .
so, what can you do? our advice would be to spend more time in the design phase - iterate, iterate, iterate until the screen by screen mockups are final, then speak to developers. this will enable developers to have greater clarity of the project and as a result, a much more accurate time and cost estimate! :)