Prolific is one of the biggest and most respected names in the paid study/survey business so the chances of it vanishing without paying you are extremely slim, so I would say you are fine. I personally would move it to my PayPal for 0 risk of losing it.I just also started Prolific last week and have done 7 so far. I don't need the cash right away so is there any reason to not just let it build up to say a few hundred pounds before I make a first withdrawal in your opinion?