Here are some of the factors that can affect the value of a SM3 Martin guitar:
* Condition: The condition of the guitar is one of the most important factors in determining its value. A guitar that is in good condition, with no major damage or repairs, will be worth more than a guitar that is in poor condition.
* Age: The age of the guitar can also affect its value. Older Martin guitars are often considered to be more valuable than newer guitars, simply because they are rarer.
* Rarity: The rarity of the guitar is another important factor in determining its value. Some SM3 Martin guitars are more rare than others, and these guitars will typically sell for a higher price.
* Celebrity ownership: A guitar that was once owned by a celebrity or famous musician can also sell for a higher price.
If you are interested in buying or selling a SM3 Martin guitar, it is important to do your research and make sure you understand the factors that affect the guitar's value. You can also consult with a guitar dealer or appraiser to get an accurate estimate of the guitar's value.