normally in paid game, one payment in an account is enough to make players play however they want it.
please, don't milk a single players more than necessary, please make house (and stable) shareable in an accounts

anyway, any kind of abuse won't happen if everything takes player's progress into calculation. e.g. daily rewards that has increasing rewards based on level/story progress/ap/overall game-time effort, so even if a players has multiple alts, a newly created alts won't be enough to help anything for the upkeep, but well developed character will help, and no one will call that as an abuse, because there are game-time effort spend already.

simply enough this game has been failing in rewarding effort of a player in a fair manner...
more effort, more reward.