How do i know if i have a bad habit, or an addiction?

A: Whatever description is most helpful to you.

I’m a pragmatist: some people might find the idea of having an addiction shaming, and others may find it supportive. 

Addiction is when someone person repeatedly (perhaps compulsively) engages in a behaviour or uses a substance despite harmful consequences, usually including experiencing cravings, and they experience difficulty stopping or controlling their use. 

A bad habit is a repeated behaviour that is harmful, unhelpful, or misaligned with a person’s goals, but which is relatively easy to change - compared to an addiction.

So, according to the above, if you can easily stop your porn use, then it’s a bad habit, and if you can’t, then it’s an addiction

But that’s not necessarily very helpful when it comes to actually stopping (see above RE feeling shamed / supported). Pornography is a behavioural addiction - so whats ultimately needed is behaviour change, and, the deeper it has its hooks in you, the harder it will be to get unhooked. 

On my journey to stopping, I viewed myself as having a low-level addiction, because I could have long periods between times using porn, but i would always come back it. Stopping for good took a lot of soul searching and support.