Group size
The advantage of big group size is always high chances to that traveling in the big group can make cheap travel in Nepal and Tibet. Because in big group size one does not reduce the airfare and permit fee. But the sharing of vehicle, accommodation, guide and porters in big group is definitely make a cost cheap. Even here you have interesting, the pair number of the traveler like: 2, 4, 6 and 8 in a group is best then un pair numbers. Because in the un pair numbers of the group size, traveler might need single room and single porter.
Making New Friends
Travel in a group, you will always make some new friends. You can explore various person with different cultural, religious. Discuss about new things is always fun, not only within trekking participants also with your trekking staff as well. While Big trekking groups size have more porters and staffs accordingly.
Restricted region in Nepal
Trekking, climbing and expedition in the restricted areas of Nepal, where should be minimum 2 trekkers in a group. Department of Immigration does not issue permit those mention restricted area for single trekker to the region like Kanchanjunga, Manaslu, Upper Mustang and Nar Phu.