Among all photographic accessories you may wish to purchase, I found two accessories that will, very likely, be underused - camera bag and tripod. Face it, unless you are taking longer vacation trips, the urge to carry all (or most of your lenses) will not be there. Perhaps, to satisfy your short-term fanatical craze of carrying everything around, you may do so initially. But soon enough, your logical mind sets in and you then carry only your primary lens and flash wherever you go 80% of the time. Your bag will begin to collect dust as all remaining unused lenses will be in the dry cabinet.
As for the tripod, its again mostly for night photography, where scarcity of light forces you to shoot with one. The sturdiness of these device often means encumbrance (unless you have a carbon fibre make) and yes, I still do carry one when I shoot longer distance with the Nikkor 70-300mm lens. But the number of days I seriously depend on one doesn't go beyond my ten figures.
So, put your hard-earned money where you truly need - flash, grip and lenses. (I sure would have hoped someone told me earlier)