I don't know how many times I've seen people working the open mike circuit, in some cases for a number of years who are still stuck doing open mike gigs and working for nothing. The big question being that they don't know how to get paying gigs, bookers will only offer them open mike spots, in some cases they only get booked because they have a car and are willing to drive the acts who will be getting paid for performing. The simple answer is this;


Only YOU can make the decision. No booker out there is going to ring you and say 'HI! I saw you performing at the Bucket of Swill Pub on a Monday night in Arsefuck Nowhere and thought you'd be perfect for my show that I run on a Friday in the heart of London - How's £300 sound for a tight 20 minutes?'
To the best of my knowledge, not once in the history of people with talent Vs. People who like to appear talented has this ever happened.
If you want paying gigs, you have to ask for them. Refuse (politely) to do unpaid spots and ask for a paying gig instead. What's the worst that can happen? The booker will say 'No.' In which case you are no worse off than doing a free spot. It then frees you to ask someone else to book you for a paid gig because you're not stuck on a Thursday, Friday Saturday doing unpaid tens and driving back to Arsefuck Nowhere. (Don't let the name put you off... It's a lovely place really)
When I started here, I put in place a couple of rules,;


*Unless they were preview spots at established clubs which had good prospects of offering paid work within the next 3 months OR I was trialling new material and needed the audience interaction to workshop the new gear.

 2/ NO GIGS UNDER £50 
*This applies to within London's ring road. If the fee was less than £50, taking into account travel costs, a meal and a drink, time spent on stage and travelling to and from the gig back home plus time spent writing and rehearsing the material I'd be running at a loss.

 3/ NO GIGS UNDER £150
*Outside London's ring road - for exactly the same reasons as cited in rule 2.

However, once a promoter discovered that I was doing this then only ever offered me gigs that paid £150. I was getting plenty of work but the fees were all £150 and some of the distances travelled were phenomenal! As a result I had to put my rates up. So now, I don't do a gig in London if it is less than £100 and less than £200 outside the ring road. Nett result, I work less but earn more, much more because my weekly amount earned is the same as what I was earning working 5 nights a week, but now my travel costs are less than 50% of what they were.
So many people out there call themselves 'Comedians'. In my opinion, if you are not treating this career like a job, then you're not a comedian, you're a day player, a blower of jokes occupying space and time until you eventually die with nought but unsung laurels. There is a serious side to being a comic, and it's bloody hard work if you do it right. You write, you engage with people you perform, you rewrite, you practice you hone your scribblings until they are sharp succinct splashes of prose, perfected for your delivery, your facial expression (is it any wonder comics get pissed off when someone steals their material?). You spend days and weeks and months on the road, which sounds glamorous to the uninitiated, but the fact is you see a lot of road, a lot of airport, a lot of hotel room. I've been to Bucharest, what did I see? Nothing! But the airport, the hotel and the venue. There wasn't time for anything else. We don't have the luxury (often) of taking a couple days off to see the sights. There is rent to pay, phone bills to clear and food to put on the table for loved ones. You justify spending a day to see the museums and art of post communism era eastern bloc when you could be earning £300 in the next city for one performance which means one day I might be able to send my daughters to a better school. At this stage I'd settle for saving enough to simply go home and see them!
So how do you know when it's time to ask for paid gigs. Only you know the answer to that particular bugbear. But here is a simple litmus test. Go and checkout some shows, see the quality of the acts that are being booked for a 20 min paid spot. If you honestly think that you can do better. Then it's time to start asking. No if's and's or but's - START ASKING. If you don't think you could entertain a crowd, the way that they are entertaining a crowd, then go away, write more, perform more until you think you can. Then, the world is yours. Go on. Take it.