Maintaining a proper level of finish on your log home is a key piece to keeping it looking great. It is also important to maintain the finish to avoid expensive repairs.
One thing I would say most owners don't understand is the diminishing returns of waiting "one more year" to reapply the stain or finish. This is what I mean: Stains on log homes last between 2-6 years. Now when I say this, I understand that this is a wide range. How your logs are going to weather over time is a function of the stain you choose, the specific conditions of your site and even conditions on a given wall.
The difference between having to simply re-coat your logs with stain and having to blast off a failing finish can be as little as one year. I see homes one year and they look "fine" they just need to be cleaned and refinished. An annual light washing of the logs is recommended to increase the life span of the stain.
Why is this? Well - it's all about the base. If the stain is broken down (very faded, peeling, or rubbing off) it is not a suitable base to accept a new finish and then the old finish needs to be removed.
To avoid the expense of having to remove the finish on your logs, it is best to maintain your finish in top condition. Maintain your log home by re-applying stain sooner rather than later. It's good for your logs!