it's tough to say, depends on how much you keep in your wallet. but, if you have something to the tune of 10 million XP staking ( in one input) probably looking at around 30k stake after couple days coin maturity, then it becomes (2 inputs which is 2 inputs of 5 million xp) once that first input stakes. then your chances are reduced but still expect a decent 10-20k xp around day 3 total (with your now split 2 inputs of 5 million each). this has been my experience with XP, i use the advance coin control features to recombine everything into (1 input) every few days or every few stakes to increase odds/ amount of staking. so over a month, that ten million could gain you somewhere around 270k XP in a month, over a year perhaps 3.24 million XP or about 32.4% ROI for a low end estimation (again purely based on what ive seen staked on average with a similar amount, could stake much higher on a good day) i think 30% is the low end for XP return, though

 (this might become obsolete knowledge once the masternodes are implemented, some older POS coin wallets (such as diamond coin) have the coin control feature automatically built into the wallet ( that is they recombine your inputs at every stake for you increasing your daily staking chances)

one thing i do know for sure is that anything less than a few million XP balance will have trouble staking as they are competing with a lot of larger balances out there.