This is maybe a bit pretentious, but I wanted to tell that long ago. Something coming here on a regular basis is how hard it is to get momentum, to keep the motivation and going ahead when you are tired etc.
I found that the best solution is to sell. It does not mean that you need to sell a lot, even if it is just $50 a month. Do it. Offer a paid option of your webapp and sell.
The days you will be down, the serendipity will be there and you will get an email from your payment processing gateway: "$50 for you". And this is the best thing you can get, it means:
"Me, the customer, trust you, you have a good product and I am ready to pay for it. You are good."
When you are offering both "totally free" and "paid options" the effect on the moral of getting a sale is higher than the inverse of your conversion rate. It is like drug, you want more of it, you start to make crosses on your year calendar on the wall, you feel good.
Go sell and enjoy accumulating these little red crosses.
And you, what is keeping you rolling? Do you think that in your case you cannot sell right from the start?
1) Do you think that having a sell angle on your site can be a traction killer? Will you be stickier if things are free and happy for a longer period of time?
2) Isn't integrating with billing solutions and going through all the necessary legal/tax/yada rigamarole the exact kind of "dip" that tends to demotivate people in the first place?
3) Isn't the customer service that comes with keeping your paying customers happy also the kind of thing that tends to take away from development momentum? Esp. if you are solo?
Would love to hear what other people have to say. I think this is a great question.