It depends on what you've got ; we have a 3.9 for the barbecue strapped inside , that's a portable barbecue not a one attaches to the van # don't carry neither bottles in car # & my 6 kg for main gas , had both over 2 years and that is away for 2 main holidays 2wks away and BBQing every day twice a day and away every 4 or 5th weekend . Could off probably gettin away with taking them this year but I have just renewed them just in case !!