Charge before or after extension?

If you have a client that is waiting on K-1s or some other information, do you charge them for the return at extension time or when you file the return, or some now and some when you finalize? 99% of the time I make clients pay before I file, but would like to get paid now for some of my efforts. Have several clients waiting for K-1s this year.

Thanks!

I feel like these kinds of things are best carried out when an expectation has been established in advance and can create an issue where none exists when people are surprised.
There are a number of things I intend to change in my practice along these lines, but I won't be making those changes in a general sense until I'm comfortable I've created a solid expectation among my clients.

I've always waited to bill clients when I've completed their returns. My practice is down to completing returns on a pay per return basis which is quite expensive. If it was getting close to October 15 and there was a question as to whether I would receive the information to prepare the returns, I might decide to bill them for the extension at that point.

In those situations, I typically bill a progress fee and then bill the remaining upon completion.

This is why ALL clients pay me no less than a 50% NONREFUNDABLE fee to ensure my availability, because it means I cannot take on other potential clients. They're reserving my time. Only a couple clients have yet to pay anything and that is my fault.

I have clients that the returns are done but need to be extended.
-Some are waiting for K1s,
-some need time to fund a SEP so we pay all taxes owed with extension,
-some need more time to gather the taxes so we pay all states, and as much as possible to the feds.

All of the above receive a progress bill if there was substantial time invested.

Always chasing that YTD P&L game (for myself).

When the returns are substantially complete and the client chooses to extend for reasons that are outside of my control (e.g. waiting on cash to make retirement account contribution, waiting on foreign tax return for FTCs), I will do a progress billing.

Others I usually don't bill for an extension.

I am mulling moving toward a 50% retainer due upon engagement letter execution next year. Perhaps I'll test it out on new clients first.

Most new clients require a retainer for anything (non-refundable and non-transferable in ANY way - it's for that year's income taxes only).

Current clients so rarely stiff me or disappear that I usually just wait.

I suppose I am leaving capital appreciation on the table and exposing myself to some non-payment risk. Some clients die too here and there I guess.