I would strongly advise against using methylone on a daily basis.
My experience and (albeit limited) knowledge of the literature on similar substances suggests that using a monoamine releaser over a daily basis is nearly a surefire way to wreck your biochemistry.
I'm recommending people lower their doses so as to prevent possible neurotoxicity (and other negative aftereffects such as mild depression, lethargy, etc). I'm not recommending that this be combined with a plan to use more often (which would at the very least probably counteract any positives from taking smaller doses).
And as you say, it has a slight addictive quality. If one were to use it repeatedly for days on end, then the likelihood of this addictive quality increasing would be very strong.
Stay safe, stay smart.