Importantly, if there is a change in the time it takes, ie when it starts to take longer to get your money, this is a sign that things might not be ok with the site and you should be wary and about using them, and get any money you do have in there out as soon as possible.
As ever, The Gambling TImes have this covered on their Payout times reports page. Makes for interesting and excellent reading, especially the slow paying at BetButler at the moment.