I see this a lot. A comedian will get their 20-25 minutes or maybe they will get a solid 45 minute set, and then you never see them unless they are getting paid to perform. Then, more often then not, you watch them struggle on stage and they blame everything, but the most obvious: You are lacking stage time! Stage time is more then just getting up on stage and working towards new material or sharpening old stuff. I look at stage time like athletes look at practice. You go over the stuff you plan to do so when you are in a real situation it comes out more natural.
Getting up on stage regularly helps “knock the cobwebs” off of material. Sometimes you have a joke that you are really comfortable with, and so you stop performing it at open mics. Then, you get on a stage during a show and try it out and you lose your place and forget where certain parts go into the joke as a whole, this can be diminished with trying that joke every so often. Here is something I do: Every so often, when I’m at an open mic, I will just do material that I haven’t done in a while, but I really want to keep in my set. That keeps it fresh in my mind so when I do want to use that material in a show, I am not lost.
Stage time also keeps that “comedic edge” about you. Comedic edge is the ability to make the funny seem natural. The best comedians in the world keep their comedic edge easier because they work more often then comedians that only get a couple shows a month. They are able to control the room because they are so confident in the material and where it is going. This is important for all comedians, especially those of us that play in bars a lot. You need that edge to keep the crowd on your side. If you are fumbling around, how are you gonna convince the audience to keep listening to you?
I get it. Comedy can be a drain sometimes. You are out at open mics for hours for three minutes of time. If you get a guest set, you have to drive down to a club and pay for parking and all of that, but if comedy is important to you as an art form and as a means of income, then you owe it not only to yourself, but also the audience that paid to see you. Don’t you want to be the best comedian you can?