Bomber Command standard tour was 30 ops, but this was sometimes shortened if training requirements dictated a need for instructors. 2Group did 20 ops due to the hazardous nature of daylight ops. A 2nd tour could be undertaken after the 6 months of 'rest' at a training establishment. Again though this didn't always have to be a strict limit. A 2nd tour of 20 ops and a crew couldn't be called upon again. However, it was uncanny how many crews were lost early on a 2nd tour. The chance of surviving a 2nd tour was 1 in 40. Pathfinders did a double tour of 45 ops! As for evaders, if they had been assisted in evading its doubtful they would return to ops. Due to the knowledge they had acquired of the people and routes, it would be unwise for them to return, in case they fell next time into enemy hands.