If you do the positioning right and create a perception of value the prospect will be more likely to agree to pay earlier. If you have not created an impression of value then putting your foot down in this area carries the risk of losing the business to a competitor or just getting a flat no. But done right this will earn you the respect of the client. So think positioning rather than closing. Ideally, the closing is a formality, a logical conclusion reached based on your prior positioning and needs discovery. It is also helpful to explain at the outset of the conversation what is paid work and what is not.

1. Scope of services
2. Specific resources to perform work
3. Change in staff terms
4. Price
5. Termination notice and penalty
6. Late payment penalties
7. Payment terms (net 30 etc)
8. Revenue sharing
9. Equity sharing
10. Intellectual property control
11. Indemnification
12. Etc.

This difference in valuing different aspects can be useful for reaching a mutually satisfactory outcome and getting past a deadlock. There can be give and take in different areas.