Following up with potential clients?

I am just wondering how everyone goes about following up with potential/former clients that have contacted you for your services.

Here is the backstory on my situation:

- Potential client (co-owner of restaurant) contacts me wanting me to take photos of restaurant and food for menu and website. Asks me to give him an estimate.

- I send estimate and he says he needs to go over it with other owner. Gets back to me and says they are fine with estimate and ask about my availability.

- I send them my availability and he asks me to send him my phone number so the other owner (head chef of restaurant) can get ahold of me with all the details and arrange a time to meet up to discuss things in person.

- I send my phone number and he says they will be in contact with me later that week when he returns from business trip.

- Week goes by and I hear nothing so I message again. No response.

- Two more weeks go by and I message again. No response.

I am curious as to how many times people try and contact potential clients? I do have the cell phone number of the owner that is supposed to be contacting me but I do not know if I should be calling that trying to reach them as well. As this has never really happened to me before, I'd love to hear from those who more experience than me. I don't want to come across as unprofessional.

Following up is being professional, but at some point you have to accept that the ship has sailed. My experience is in another industry. We'd regularly follow up on proposals that have gone unanswered. It's just good business practice. Calling once a week doesn't seem too pesky to me.

My experience is in wedding photography, if an email goes unanswered, I will send a follow up 2-3 days later (if communication was quick and regular before the drop off). After that I wait another week. Then 1 month. If still no answer I write it off as a dead lead and move on. Sometimes several months later the potential client will reach back out but very seldom.

I should mention I have had previous dealings with this particular restaurant and it was a little bit difficult to get in contact with them as each person would pass me off to the other.

I just wanted to see what others did as I want to show interest in the potential job without appearing pushy, while not wasting my time on a dead-end at the same time.

Thanks all.

I am in the same business and find that most are window shopping, not ready because they're still developing recipes ornate prepared to spend the money. It sounds like you've done what you can and anything else would simply be too much.