Spark startup time

Question

Time to initialise our Spark application is now approaching 10 minutes! That is ridiculously slow, what can we look at to improve this time?

It's a small pool - and while it's configured to allow up to 80 nodes, the jobs we run are relatively small but we run many at once - and while running many at once seems to suggest the cause, it shouldn't since each job will only need the 3 nodes (and certainly only 3 at initialisation)