It doesn't except that you have to pay a transaction fee each time your miner sends a proof to the contract on Ethereum. For optimal results in the long term, it would probably be best to only try and solve the hardest problems at the lowest frequency because the mining period is about six months. If you mine at a difficulty level where you're most likely to find one proof per week, your results will still be quite predictable because the mining period is almost 26 weeks long.
It doesn't except that you have to pay a transaction fee each time your miner sends a proof to the contract on Ethereum. For optimal results in the long term, it would probably be best to only try and solve the hardest problems at the lowest frequency because the mining period is about six months. If you mine at a difficulty level where you're most likely to find one proof per week, your results will still be quite predictable because the mining period is almost 26 weeks long.