Hi there,
disadvantages of pendrive are:
1.gets virus easily.
2.u will only realize until u infected someones computer. 
3.we need to format it to clean in,loosing every data.
4.gets lost easily
5.dont have lots of life span
i hope this helps u..
i dont think life span has anything to do with this
it has
what does it have
i have 4 pendrives ,2 of them stopped working ,i bought them 1 year before
ohk i think it would be better if u jst said shot life span
>they can get lost easily because thry are small
>they can get viruses 
>they can get stolen easily due to them being small in size 
>they can get corrupted 
>it can break while moving the usb