I work freelance for a UK property company. I've created an Excel model to perform viability appraisal analysis on single phase property development projects. It: captures inputs for areas, values, costs, inflation, interest rates, timescales etc; generates a monthly cashflow schedule; has several output reports; has macros to calculate land value, insert new rows etc.
It now has to be expanded to handle 8 phases. I've divided the structure between Project-Level and Phase-Level. I've copied phase 1 (which is spread across 9 sheets) to create phase 2 (in the same 9 sheets but underneath phase 1) and I've corrected the fixed absolute cell references and setup phase level macros. I now want to outsource, through vWorker, the copy/paste/cell-ref-fix/macro work for phases 3 to 8. Each phase must be tested with test data to ensure it is isolated from the others (no bad cell refs) and with the same inputs, gives the same outputs.
I am very familiar with this model so I can make good estimates of how long it would take me to do the work. So, for someone new to the model I reckon on a week made up of: 1 day familiarization, 3 days creating the 6 phases (you get quicker with each successive phase), 1 day testing. Say 40-45 hours. It's meticulous work (and rather boring after a couple of phases!). But it's important it is done correctly.