1. how much time is needed to get this idea off the ground, 2. how much money is needed to get this idea off the ground, 3. how many new skills are needed to get this idea off the ground, 4. How much will I still enjoy building this a year from now?
Sometimes an idea is just too big or ambitious at first and this helps me sanity check it.
After that I like to validate my idea - for that I need to learn if people are:
1. interested in the idea 2. willing to pay/use it
I always recommend keeping it simple, fast, and cheap - customer interviews, landing pages, mock ups, etc.
This example from buffer - https://blog.bufferapp.com/idea-to-paying-customers-in-7-wee... has been around for a while but I still like to point it out as a good way to test a concept and see if people are willing to pay for it.
I'd love to hear what you are working on, I'm a business coach and do a lot of free coaching for new startups ping me if interested jarrett@startupdaybook.com
MVPs should be "easy", dirt cheap and highly accessible. If shit breaks because too many people want in, then that might be an idea worth building on. If the app is too hard to build and isn't getting traction quickly, it might be too hard or the wrong thing.
I.e. I posted a website with a basic concept of what I could provide. After the first person signed up, I started building out the infrastructure.