How long do you wait until you admit to yourself that you have been scammed?

Everytime we buy things online, at least for me there is at the back of my mine the question of is this legite or a scam.

Sometimes things get delayed in the post by a few weeks (in one case a few months) but in many times, my patience has paid off.

So how long do you wait until you admit to yourself its a scam? I still have websites that i paid for development that are "2 years late", and again, i have hired yet another fuckwit from DP to perform SEO on one of my websites, yet here i am, at the end of the month with just a few days left to be able to do a chargeback, and its starting to look clear that i have been scammed again.

Am i the only idiot here that repeatedly waits for people in good faith and repeatedly doesnt do chargebacks when i should be doing chargebacks for nearly every transaction that i have done on this forum? I am just trying to work out So at what stage should i admit that i have been scammed? should i wait another 2 years or waste a week attempting a chargeback and having paypal laugh at me?