First Tommy_37,
Brand of E-Cig - important, but not that important in the beginning. E-go is popular (has Ego threads), Smokless Image Volt also popular has KR808D-1 threads (inexpensive adaptors allow you to interchange cartomizers, tanks etc). I started with the Volt Kit and added to it with larger batteries like the X2 from Smokless Image. That is not to disparage the E-go which many like also. If you then enjoy vaping as you probably will you can plan your next purchase up to a Variable Voltage device or the the ProVari which many consider to be one of the best (also very expensive). I recommend a kit at first because it comes with everything you will need including charger etc. OK forgot your health question. All I can say is that I had my semi-annual Dr. visit yesterday and when I told my Dr. that I had quit smoking and was using a personal vaporizer, she put me down as a non smoker and congratulated me. No comments what so ever on not using a vaporizer to replace cigarettes. I guess that says something.
Will19,
It is OK to charge your battery whenever you choose. I have heard that charging prior to letting it go to empty is actually better. Batteries claim up to 300 charge cycles. If you charge it before it goes to empty, it will increase the number of times you can charge it.
Throat itch, sore throat, dry mouth, ulcers and a few other nasty problems may occur. Read up on the forums on vaping effects when first starting. Mine tended to be mild and went away in a few days. Drink pleanty of fluids especially water when you vape. Throat hit comes mainly from the nicotine level. I started at 24 and it was way to harsh. Gave me a sore throat. I went all the way down to 6 mg nic and found that was too low, so now I am at 12 mg nic and it is just right. You need to find a level where throat hit is satisfactory, but not too harsh. Some people can't tolerate PG which gives better flavor I am told. VG gives more vapor, so 50/50 seems a fair trade off. That is the blend I use. Best of Luck.