You could consider investing in some training for the employee. You could have another senior designer offer the critiques and feedback you feel are eating into your time.
You most certainly should charge for maintenance. Depending on the size of the project, you can also charge a monthly retainer to be available for maintenance should the need occur.
Constant fear of Apple breaking backward compatibility by shipping new versions of their operating system every year.
Apple is now running a beta versions of iOS 8.x and iOS 9.
This puts a massive brake on the impulse towards creating new products if you have fixed resources. It creates a strong bias towards optimising existing products even after the point of diminishing returns.
I don't think finding a unique SaaS idea is the way to go. You're better off studying the competition and trying to see how you can sufficiently differentiate your offering from them and creating an overall better service.
If you or your team have strength or experience in marketing, you can even create a clone and out-execute them on the customer acquisition front.
There are still vast swaths of businesses that use paper and pen and Excel for many things. So your competition will not be other SaaS offerings but, in fact, no solution at all and not even looking for one. Converting them to your solution is the hard part.
Alright, so here's how you go about it. I'll first give you the general approach, then an example.
1. Find a demographic that you care about. Someone you want to help from the heart (not just intellectually). This will keep you going through the dark times.
2. Find an online forum or vertical where a critical mass of this demographic hangs out. This could be a specialized forum, a subreddit, or twitter.
3. Read through their posts and find pain points and existing businesses that solve these pain points.
4. Create a SAAS that helps these businesses you found above. Typically you can help them become more efficient at something. They will most appreciate a SAAS that helps them book more customers.
Here's the example I promised:
1. Let's say you care about pets and pet owners
2. Spend time on /r/pets and /r/aww and find their major pain points
3. You'll see that vets (veterinarians) and animal shelters come up a lot.
4. Look at Vet websites and animal shelters and see how you can make them better and offer differentiated services for these vets and animals shelters as a SaaS (note, these are businesses and you're thus a B2B SaaS).
That's how you come up with a good first part of the founder/product/market fit equation :)
Execution is a whole different ball game and then there's the marketing. If you've done your research right, then feedback and early customers should come from the very forum that you discovered the pain point at.
Your motivation will come from knowing that by improving the services offered by the vets and animal shelters (even if it's in the billing department), you'll be helping a lot of kitties and puppies at the margin.
This is the only way I know to do meaningful work and make some decent money at it.
TL;DR: Find a demographic you care about; climb one or two nodes up the tree until you hit a business that serves this demographic; create products/services for these businesses.
For B2C products, once word-of-mouth and customer referrals become a significant (~10%) chunk of your customer acquisition, it's safe to say you have good product/market fit.
First, think of what you will do if your client refuses to increase your rate. What is your BATNA? Are you prepared to walk away?
If, after rejection, you plan to continue with the client at the same rate, you will need to make sure the negotiation process does not sour the professional relationship moving forward. This means making sure that you're emotionally prepared to be rejected and also negotiate in a manner that does not come off as aggressive or manipulative.
The best way to ask for it is to highlight the clear benefits you have delivered already and to paint a vision of continued benefits moving forward and then ask for your new hourly rate. Ultimately it's as simple as that.
You will need to overcome objections be referring to the "market rate" and positioning yourself as referring to objective external standards.
Like Patrick mentions in his reply, you should try to hack your psychology to get more comfortable with directly but politely asking for things you want.
One trick that works for me is to tell myself "Let's try it and see what happens". Curiosity is a strong motivator.
This is a deal-breaker for me. I don't want to risk putting years of effort into this and then have the app break when Apple decides to deprecate APIs in their next OS release.
Having said that, you should be charging much more.
Good point. While the family Corvidae (Corvids, which includes Jays) is found in South America, the genus Corvus ("Crows") is absent there. So for PBS to be correct you have to read "Crows" as "the Crow family".
[0] https://news.ycombinator.com/item?id=10924605