Like someone mentiond, it's very individual.

I have a friend, call him Y, who pawned his television and sold his fucking passport(!) to obtain cash for dope.
Y got clean, and now he takes oxycodone on occassion. He doesn't drink, so he popped oxy on new years.
Then he didn't touch it for another two months. Railed a 30 at a party.
It's been three months since then and he hasn't touched anything.
No cravings or nothing.

Then there's me.
Whenever I've been clean for the past five years, be it from weed or pills, it's always the same thing.
I had this long stretch (like one month, haha) where I quit smoking cannabis.
Then one weekend, hanging out with my siblings, they offered me a toke.
I was like, fuck yes. I've been good. I'm just gonna smoke tonight.
The day after, I got a bag of hash.
"Just for the weekends", I said, but sure as fuck I smoked everyday until that bag was empty.

So as for me, it's a no-go. I get clean, I gotta stay ​clean.

You jus gotta feel yourself on this one. Ain't none of us who can say yes or no.