Hank, my business is 75% repeat and referral. I touch my client base at least 2-3 times per month throughout the year.

Oh yes, I would definitely stay in touch more, esp if you want them to refer friends to you.  I've started to do a quarterly card w/ tips about their home and/or floors (as I do floors).  We do a 1 yr anniversary card too and they get our email newsletter monthly (unless they opt out).

If they refer a friend to us, we send them $50 gift certificate to restaurant.com

Cards, phone call, email and in person, pick one once a quarter and that works for me. 

I agree with Roy, it is nice to pick up the phone and say hi!  One of our clients stays in touch as least once a quarter!  A

Pick up the phone and call them or just drop by to ask how all is going. The personal notes are nice and may be saved but may not incite a call to you.

Always - every month.

I think one should ask themselves, "Am I going to subject my past clients to an Exlax plan (you know what I mean) or will I implement a plan that actually means I care?"

Hey, the reality is, some agents don't care and are simply working the numbers.

Some time ago, you were able to instill sufficient trust in this person for them to conclude a transaction with you. If trust building was your intent, you should understand that maintaining that trust only requires a little tending, not persistent badgering (referred to earlier).

If you really care, let your followup be based on observation as it relates to your knowledge of that individuals passion, challenges, worry, profession or hobby.

Remind them they trust you and you in return trust they will introduce you to their friends, family and work associates. 

How you recognize the focus of the clients passion at the time of closing will go a long way regarding the ease you will experience in tending the garden of this union of aligned interests.

Final word. Do something that affirms...they matter.  Observe and remember. At the time of the trigger event or every 30 days for 5 star or 90 days for sphere, touch base with their affirmation.  In less than 10 years this will account for 80% or more of your business. Use a PAN letter, an invitation or a phone call. Why? Becuase they matter.

I used to keep in touch regualrly but have not been doing it recently. I hope to do so in 2015.

I sent cards to all, some with gift cards, many text messages, some social media greetings, emails, follow up calls.

Drip campaign and monthly item of value are important as much as popping by once in while. (My coach recommends once every quarter - however, I do once in a year only!)

We stay in touch monthly with all of our past clients. Our only rule about what we mail them is to make it different every single time. Frequently it has nothing at all to do with real estate. We dream up funny ideas that will compel them to open the envelope. After all, we are just reminding them we are still here. They already know we sell houses.

I use a newsletter to stay in contact, ideally on a monthly basis but sometimes I skip a month.

I put all of my past clients on my monthly community news letters that go out.  It also features home tips etc.  I also send out a Quarterly Report that they get.  I send a mailer (post card or letter) every two months.  It is amazing the amount of clients that I get are repeat or more referrals from them...as so many times past clients have "lost" your information...so staying top of mind really increases your chances of them referring you to someone else, or contacting you when they need to buy or sell again. 

I also send Birthday Cards, that are hand written with someone that I remember about them.  

I find it is important to keep a database on my clients on how many kids they have, what they like to do etc.  It is great to bring that up when writing a small note to them.  

I always make sure to hand sign my letters that I send out, and hand write all the envelopes, I find they actually get opened this way. 

Dipti nailed this one!

All the time - meet them in person many times during the year.

I started using a crm a few months ago, not the best contacts, but better than nothing.

It varies by client.

Newsletters are a good resource and calls or email drip.