Frankly, it doesn't matter one way or the other for me if my client is still using a paper system (for calendars, contacts, etc) or an electronic one. As long as their system works for them, I don't bother with it. We move on and work on something else. HOWEVER, if their system is NOT working for them, then that's when we have some discussions.
I'll admit it that when it comes to technology, I can go kicking and screaming, dragging my feet into using it. No kidding. I believe if you have something that ain't broke, don't fix it. I also believe that technology changes too quickly and there's always something "better" out there, so that people feel the need to get new phones, laptops, and software every 6 months just to keep up. Yet, that doesn't mean the new stuff isn't bad, and may be worth looking at, even if everything you already have works fine.
Paper calendars are very good tools for the visually inclined, especially those who doodle and like to scribble notes. I was one of those. I would remember a particular date or address because of a doodle I had drawn on that page, or the color of ink I had used when writing it down. Not the most scientific way of remembering, but hey, it worked for me. What didn't work for me was the number of contacts I had and their information and my way of retrieving it. Plus in my business, I have to keep up with what many of my clients are using. It was the job that convinced me to go digital, and my smartphone obsession was born. Ok, it's not an obsession, just a deep, deep respect for what it can do for me.
A smartphone can take some getting used to from someone jumping from a paper system, and there will be a short period of feeling uncomfortable, but everyone I've worked with (and even friends that I don't work with) that I've encouraged to take this step have never regretted it.
Paper System (including datebook, rolodex/address book):
Pros -
- it's visual, and writing info is a snap. It's tactile, so it feels good going through the pages. And most likely, it's easy to read.
Cons -
- changing dates/names/numbers etc is messy. Unless you write in pencil, your paper system could be full of crossouts and messy scribbles. Moving dates around is cumbersome and ugly.
- if you lose this, you are screwed. Royally. Unless you've taken the time to make copies on a daily or weekly basis as a backup, you have none. All of your critical info is gone forever, which could make a huge dent in your business/work.
- your system could be big and bulky. Even with a medium sized datebook, it's thick, and doesn't fit well in smaller bigs. And are you carrying your entire rolodex around, or a subset (and then you're missing some information you may need)?
Digital System
Pros -
- combine your smartphone with your computer and you've got a system that is easy to access from anywhere. Your entire rolodex, all of your dates (from now until years from now), it's all at your fingertips.

- the system has redundancy. If you lose your smartphone, and you've been syncing your info to your computer, there's your backup, And vice versa. You now have peace of mind that you will not lose your critical information.
- information is easy to change. No more scribbles or crossouts. It's so easy to move dates around, change times, email addresses, phone numbers, etc. And with people changing jobs and living spaces, it's nice to know this won't take long.
- color categorize. Some systems allow you to color categorize, which makes finding information at a glance even easier. And for those visually inclined people, it also makes it easier on the eyes.
- faster retrieval. I can find information so much faster on my smartphone or computer than someone with a paper system can. It's proven, and effective, which is important in business when time is money.
Cons -
- learning curve. Yup, it's something you have to learn, and for the techno-wary, this is a scary prospect. But jump in. You really have to, because that's the way the world is moving. And then you'll find it's not that bad.
- expense. A smartphone and a computer are going to cost a helluva lot more than a datebook and rolodex. Chances are, you have a computer already (how else are you reading this?), so that's one less expense. Most likely, you already have a cell phone, so really, it's not that big of a leap to get a smart phone. And there are some good deals out there, if you have the time to look.
- apocalypse. If something should happen where we can no longer have electricity, then all of our info will be lost, unless you've printed out backups on a regular basis. You can no longer use computers or cell phones to get your dates and contact info out. The upside is, that no one else can either, so you don't have to worry about email address or phone numbers. And after an apocalypse, I just bet that 9:30 meeting with your clients/co-workers has been cancelled.