the first one is limited time contract,
you will get power based on your buy and they will set a limit for your contract such as 1 year,2years and something like that.
the second one is lifetime contract,which mean is your contract will run forever because it's lifetime contract.
but the facts is no matter what type that you choose or buy it has a limit.
what does that mean ?
the limit itself is unpredictable,you will lose your contracts if your contract no longer profitable,
no matter when is it,they will force you to close it or they will close it automatically.
it can be happen when the difficulty doubled and prices is decreasing a lot,while you can not pay their expense and their earning.
so in conclusion,no matter what is it.it has a limit.
Yes, thanks. It has a limit