The paper gives a short report on surveys conducted in the framework of the Vienna Orme and Pesa Valley Project. Focus of is laid on the comparison of two intensive on-site surveys at Molino San Vincenzo which were carried out under differing conditions in 2013 and 2016 and achieved differing results since in 2013 the visibility was much lower than in 2016 due to vegetation and therefore the only a limited number of artefacts could be found. The results of the re-survey in 2016 offered the opportunity to evaluate on-site survey methods. One of the main questions is the reliability of survey results even with low finds numbers. The pluri-methodological approach of the Vienna Orme and Pesa Valley Project enables also a discussion of assets and shortcomings of other methodologies, especially geophysical prospections and shovel-testing, in terms of their suitability to detect the sites still unexcavated.