Time Estimation for automated scripting

Hi, I am taking one real time scenario for any desktop/web based applications need to be automated e.g. Retail application. And tool to be used is QTP or TestComplete. Requirement- 2000 Manual Test Cases need to be converted into automated scripts mainly for regression testing. Main points to initiate discussion or estimating the time required- How many products are there. How many transactions are there. How many type of customer are there. Which framework is to be followed. (Most of the cases, Hybrid Framework is preferred) Way to proceed Identify key areas (primary) e.g. main functionality, financial, important feature, etc. Identify number of features e.g. 100. Identify complexity of features (medium, high or low) Divide the deliveries into different phases P1, P2 and P3. Time Estimation Go screen by screen. Identify time for single screen e.g. 45min, 50min, etc. High complexity scripts having more than 10 screens normally requires 8 hours time. Medium complexity scripts having less than 10 screens requires 4 to 6 hours time depending on the number of screens. Say you have identified that applications requires only 100 scripts, now divide all deliverables into different phases- Phase1 - Study the application and gather requirement. Phase2 - Deliver 10 automated scripts (mainly key features). Phase3 - 20 Scripts Phase4 - Another 20 Scripts - - And so on.... Implementation Choose products Use parametrization using local/global sheets. Do record/play in the initial phase. Enhance your scripts by applying various checkpoints,etc and see the behavior. If things goes well, then it is good otherwise go for descriptive programming. Create actions per transactions. Identify transactions that can be reusable e.g. login, logout, various actions to be used multiple time in the application. Applying Recovery Scenarios in case screen is stucking at some point/