I bought a waterproof(small drybag) kit, and added a few things in it. A bit of Sterilon, extra Tickpinchet(once I had in one week 34 ticks) and some ointment for light burnings(also already used it, though it went leak a bit). Also added some Paracetamol.
I tend to keep it organized. It once was in a little closable plastic sac, Now I keep the emergency things(wounddressings) apart from the not-so-emergency things (plasters for example). And always keep the emergencyblanket and Lifeshield resuscitator on top. I hope I'll never need that stuff.
And indeed, as Jura says; have a kit based on your own level of competence, confidence and environment.