When does renting hash make sense?
I've seen this question posted in a number of places around the forum and thought I'd write up an explanation that will hopefully help you make a decision on whether or not to rent.
Things you need to consider:
First and foremost is the price of your rental vs the expected earnings of that rental. For example, if you were to consider renting 100TH/s right now, you would expect that hashing power to make you 0.3039
BTC a day. Take a look at the rental sites and compare what they are charging for 100TH/s for 24 hours vs that number. I think this is pretty obvious, but I'll write it anyway: the lower the better
Next you need to consider the hidden costs of that rental. The rental sites do not give things away. For example, nicehash.com applies a 3% fee on every order. Yes, they are making money from both the renters as well as the owners (owners get charged a 3% fee for pointing their gear there). So, this means that even if you do get your rental for exactly the price the hash rate expects to earn, you are starting at a loss. To start off even, you need to get your hash - assuming you're renting from nicehash.com - at 3% less than what you would expect that hash to make.
The next thing to consider is the pool to which you wish to point your rented hash. What payout method does the pool use? What fees does the pool charge? Pro tip: the absolute WORST type of pool you can point rented gear towards is a PPS pool. Every PPS pool out there charges you a fee - and usually a pretty high one. The biggest pool, f2pool, charges a whopping 4%. Think about that. If you've rented from nicehash.com and point that gear to f2pool, you need to get your rental for 7% under expected value
just to break even.
Finally, now that you've chosen your rental provider and the pool on which you're going to mine, take a look at the stats. How are those miners performing on the pool? Are you getting a lot of rejects? Seeing a ton of invalid shares? That will have an impact on your payout as well. For example, a lot of the Bitmain gear loses a considerable portion of its hash when pointed to p2pool. Bitmain's crappy cgminer fork just can't handle the way p2pool works and the hash rate suffers for it.
You'll notice I've written nothing about a pool's luck. Quite simply, it is not relevant. Past performance has no bearing at all on the future. You can certainly use that information speculatively, but it is certainly not a metric on which to base things.
I hope this has helped, and I look forward to seeing some of that rented hash pointed to
Bravo Mining 
