The own practical experience of an estimation of the innovation and investment projects realized in real practice is presented and the typical mistakes which authors of research in this direction assume are generalized: absence of the proved features of each project, ie the account of economic rent; mandatory sensitivity analysis when substantiating complex projects; availability and assessment of additional income at the liquidation stage of the project; careless attitude to the determination of the interest rate of income and investments that may be involved in the project; mandatory pre-planned research is required.