Safety

I found that whilst training in kendo there were a few places that took hits that were not normally hit. This is because whilst I was learning to fence with two swords, everyone else was learning to fence someone with two swords.

When you are in certain Kamae,  in tsuberzerai or even tai-atari your opponent will attempt to sieze opportunities. These opportunities may not actually be there and you will get whacked.

Elbow

A classic mis-strike is to your elbow. This is normally on the elbow of the swortsword arm. The strike attempted is normally Do.

They feint and you follow with your longsword, they see this and cut Do... but waitaminute your elbow is still there... smash..ouch.

A good safety measure is the elbow pad. A lot of budo shops now sell these, but I found that skateboard/rollerblade pads are just as good and a heck of a lot cheaper. My set was £3.50! 

You do NOT want hard shell pads. these are the ones with a hard plastic shell that covers the elbow area. They are heavy, they are stiff, and they can ruin your opponents shinai (I know thats your least concern, but still bear it in mind).

Please bear in mind that this does not give you free reign to drop your elbows or to deliberately block Do cuts. If you do this you are completely missing the point, the pads are for safety only.

Wrists

Because you now have both Kotes as valid targets for your opponent, they will attempt them.

There will be times you will get hit. I was hit particularly bad on the kote when I first started normal Kendo. leading to a bruise that lasted for a month, and the doctor said the bone was bruised, it was entirely by accident but has made me cautious.

A childs Football shinguard is a cheap alternative to the budo shop wrist guard, and for the cheap price you get two. Which is great for Nito players.