It depends....mostly upon your deer density. My property is one mile long and I have 2 distinct deer herds. On the north end where my property is adjacent to a farm that kills a lot of deer during the summer on crop damage permits, the deer density is much lower so I can sometimes get away with planting and not fencing, whereas on the south end I would really need to fence my beans to get any pods out of them. On the other hand, I can plant beans on the south end to give the deer some early season forage, knowing that I will be planting brassicas over the top of them in mid-July to get some late season forage.
This is a 2 acre plot on the north end where there is a lower deer density after having been pounded on crop damage permits all summer - October 16th
The same plot on December 5th - still quite a few pods left...
Smaller plots need to be E-Fenced - no question about it.
2+ acre plot on the south end on July 30th. If your beans get pounded like this you will be double cropping like I do...
Exclusion cages will definitely tell you the story...
All is not lost though, as you can broadcast brassicas over top of the heavily foraged beans just prior to a rain event and get a decent crop of brassicas after the beans...
I have even had good success broadcasting brassicas into standing corn...