When a prospective buyer calls my office it is one of the first questions I ask.  In fact, it has been our policy for 22 years, that we do not take a buyer out shopping unless they are pre-approved.  Pre-qualified is useless as nothing has been verified yet.

Right off the top, after some initial discussion. "Will you be paying cash for your purchase, or do we need to provide lender resources?" If they reply they are a cash buyer: "Excellent. During the offer process, we will need to provide proof that you have sufficient funds to close. Do you have that handy or will you be able to get that quickly?" Listen to the answer.
If they reply that they have a lender, "Excellent, I will send them an AZ pre-qualification form--it is addenda to our purchase contract. Have them send it back to me completed." Listen to the answer.
The more listening you do, the more you learn.

I do in the first conversation. There's always a way to bring it up without making it sound like the inquisition, and buyers usually don't mind.

I do it in the first conversation because I want to know how far along they are and whether they need to get prequalified now.

As early as possible , because that will uaually tip you off as to if they are working with another agent  !

As soon as you start working with them.  It is pointless to show them homes they are not qualified to purchase.  And if they haven't been prequalified, they need to learn the importance of getting it done so their offer has more weight with a seller.

First conversation.

At the conclusion of the first meeting.

Why?

At that time I have appraised the client, and they me, and the reality is there could exist a great incompatibility. This could be they are not yet prepared to make difficult decisions, are indecisive regarding 'this time of their life' or reveal they are in pursuit of entertainment.

If 'it's a go' I will advise, to avoid certain heartbreak, they need to be prepared. That means, "Show me the money."

First communication.  It's a great way to learn about their motivation AND their knowledge of the home buying process. 

I ask about pre-qualification the first time we have a discussion about their needs. If they call to see a house and I've never talked to them before, that's when I ask that question.

As soon as possible, unless they pay cash, so ask for POF. 

Early in the process if it is applicable to the situation.

Vanessa Aparicio - at your consultation meeting. If they are not pre-approved, connect them with your lender.

During the initial discussion. If they are not, they need to get approved and provide me approval letter and proof of funds before I will work with them.

I bring that up in our first conversation. If they haven't talked with a lender I mention the benefits of doing so. Most buyers get it. 

Upfront is the best.

Before they start looking at homes.

Right after "hello"

Hi Vanessa! 

When I work with Buyers, I ask several questions - re: is this their first home purchase, are they relocating with work, etc. - to get some idea of where they are financially, if possible. After some "small talk" I usually have an idea of where they are and if there's a good time in the conversation, I'll ask if they are working with a local lender or if they need some mortgage lender contacts. 

One of the first questions!

I do it within the first 5 minutes - it's part of my script

At first significant contact.

It depends on the lead. Buyers looking in the $200k range are treated differently than than those looking in the $600k+ range. First time buyers get asked right away, affluent buyers don't get asked. Look up where they live, that will help you decide when/if to ask.

There is no hard and fast rule, but I'd say sooner is better.

When you first meet them.  If they haven't, then it would be a good time to suggest it.

hi, my name i s vanessa, have you been pre qualified

First call after you've found out if they are currently working with a real estate agent!

This needs to happen immediately when you meet a new buyer client.  There is no point in moving forward unless you are all on the same page.  

During the first call.

In the initial interview, ask all the right questions and get everything signed.

In the initial conversation with them

Before the 5th sentence.

Whenever the question is posed...the timing is soon to follow...Richfuscious

ASAP  before they go with another agent.

Soon in the process.

If they are wanting to go out right away, in that first conversation.

At the very start!  "Hi Jim, I'm Ryan.  Are you working with a lender?  Great, what have you been pre-qualified up to?"

I ask if they have spoken with a loan officer yet.  If they say no or yes I have my answer.  I usually ask the first time I speak with them.

Right at the beginning when you are talking about their needs, wants, neighborhoods and price range. No sense getting someone's hopes up when you don't know what they can afford.

First time you talk to a buyer.

as soon as you have your first conversation with them.... and if the answer is NO, then get that job done before you waste your time....

Vanessa Aparicio Up front otherwise you may be wasting a lot of yours and the buyers time.

Right away. If you don't want to be too direct, you could ask them who the lender is they are working with... that will open up the conversation.

The second question, first is are you working with another agent

Day one, as part of my "are you already workign with a Realtor".

When I first talk to them.

At your first contact either in person or on the phone.

The sooner a mortgage pre-approval is given, the better.   

During the initial discussion with them