If you are on your 1st spouse visa then you will apply for FLR (M) which is further leave to remain and is basically a renewal of your spouse visa. It's good for another 2.5 years. You'll be eligible for ILR after 5 years on a spouse visa/FLR (M).
Generally up to half the time on your visa, but you need to convince UKVI that your absence is justified by holiday, business trips and other compassionate reasons. If you just leave UK to work abroad unconnected with your UK job, it will be difficult to argue that your absence doesn't breach the conditions of your visa. Also they will look to see if your spouse travelled with you.
Spouse visa is issued on the understanding that you will make UK your home, and you intend to settle here.