As
@shadowvaper says if you are going to stay off the fags you do need a backup of everything that you require for your vaping, stuff can and will go wrong with kit at some time.
However, before you go getting a backup and a backup for the backup, you have to find some kit that works for you and get the right strength of nicotine in it.
I personally would not advise diving in at the deep end, spending a lot of money on complicated kit. Regard your first setup as something that may well end up being your backup device once you understand more about vaping. The most important thing when giving up the fags is to have a device that delivers enough nicotine that it takes away your craving for a fag. The sort of devices listed as starter kits on this site
http://myepack.co.uk/kits.html should be able to do the job for most people. Ask here for more help in making your choice if you want. Watch youtube videos on kit that takes your fancy.
Once you have chosen your kit you have to find a juice flavour that you like, this may involve testing quite a few flavours. You buy this juice in the strongest strength that you do not find too harsh for you. Lower nic juice is smoother, but while breaking your baccy habit go for the stronger stuff
!8mg for starters, if you have been a heavy smoker. Once you have stopped smoking or if 18mg is too strong then drop to 12mg. Some shops let you test juices, if you can find one then that will save you from buying juice you do not like or that is too strong for you.
Once you have found that vaping is working for you start thinking about your backup system, read up on this forum see what kit people are talking about, watch more videos. If your first setup is working for you you may want to get more of the same or you may want to try something different.