It's always a toss-up between being inclusive and allowing people on different budgets to join your programs by offering payment plans - and asking for the money upfront.
Lots of people will tell you that only the customers who pay the full whack up front are the ones worth having - but I disagree.
Many people don't want to commit to handing over multiple thousands in one go - but are much happier handing over a few hundred a week/month.
But... there are of course risks with payment plans - so you need to be sure you're covering your financial arse should things go skywards - which by the law of percentages states - they will!
If you choose to offer a payment plan then ideally you'll want this front-loaded.
This translates to starting to take regular payments BEFORE a course starts - or, in the case of 1:1 coaching, you'll want the bulk upfront.
Because you always want to be paid for the work you've ALREADY DELIVERED - and whilst we're all realistic and know that life happens to people's finances, YOU don't want to feel out of pocket if it all fucks up.
And... if we're being SUPER-REALISTIC - let's be honest about this. You can have all the T&C in the world and signed contracts - but you're going to have to have deep pockets to chase people over international borders for a comparatively small debt! QED - here in Scotland the law is pretty firm in that debtors can't be chased/harassed.
[[Edit: 18th October 2021
NO, NO, NO!
The whole "payments plans" concept has never really sat right with me - so today I've transitioned to ETHICAL PRICING for payment plans - read more here.]]
In terms of pricing it up, I used to be too generous and not want to compare myself to a loan-shark - thinking "jeez... this is a 60% APR if I let them split-pay over 8 weeks" - but... you need to factor in the risk of failed payments - AND more annoyingly, all the extra admin that goes in to chasing up late payments.
People's cards expire, people run out of cash, stuff just doesn't work - and whilst you're trying to get the payments back in hand - the show must go on and then it's going to take admin to remove them from the course if they've stopped paying.
Personally, if I get a person who can no longer pay - then I bless them and move on. Life's way too short to carry around all that negative energy.
So when you're wondering what you should add to the 'one-time' payment to cover the associated risks to your business - the general rule of thumb is to add 10-30% to the overall cost - and you can go higher if you wish! ESPECIALLY if there's a large digital element to the course they'll get immediate access to.
If the overall cost of your program is $497 - then you can easily break that down in to 4 weekly payments of $147 - and again, front-load that so that at least 2 weeks has already been paid before you START TEACHING - so that even if it all goes to shit after the first week of working with them, your costs have been covered - and, if they're unable to make that final payment you can remove them from the course and you've still been compensated for your time.
I have also seen longer programs broken down in to $97/week over 20 weeks - and the 20 weeks exceeded the length of the course!
It's going to come down to how you personally feel about accepting the risk - and the quality of clients you're getting to work with you. Crappy clients are more likely to bail out on your payment plans... but then you need to ask yourself - why are you ATTRACTING crappy clients?
They should NEVER be coming to you solely on price/payment plan - but instead because they simply can't NOT work with you! 
