I have finished developing my product. Website, domain is all setup. Billing system is in place.
I have yet to incorporate.
I am planning on incorporating by myself as the founder.
Then I am thinking of getting maximum 2 other partners to lend me a hand with the business.
What percentage equity should be given to the partners? Could I give them an incrementally growing equity? For example, start with 5% and then as things mature, raise their share?
I don't want to straight off promise 25% right off the bat.
I agree with others.. since most of the work is done, you dont need partners IMHO. Go ahead and launch and if it gets to a point where you need more help, then hire someone. If its an enterprise product, hire a sales person if its a consumer product you will probably need help with support so depending upon your domain and technology hire a mid level dev for support.
As others have said you may or may not need partners right now. (I'm not sure if you mean financial partners or "sweat equity" type partners - if it's financial this is usually different.)
I want to address how you compensate a "sweat equity" style partner. Whatever percentage you can both agree upon definitely have a vesting schedule. A typical schedule is 4 years with a 1 year cliff. What this means is this: say they are getting 480,000 shares. They start with 0. After 1 year they vest 120,000 shares (25% of their shares) - that's the "cliff". If they quit before 1 year, they get nothing. After that first year, they then vest 10,000 shares every month (the remaining 360,000 shares / 36 months).
This protects you from giving out equity and having the person quit on you and taking their equity with them. They have to stay and work for 4 years to get that equity. This is something that you probably want a lawyer to draft up.
Exactly how much to give them really depends on where the business is at, what they bring to the table, etc. You're going to have to go off of whatever the two of you both think is fair.