How much to invest in enhancing a mitzvah?

Dear Rabbi, I would like to know if you can give me a rule of thumb on how much I am obligated to enhance mitzvot. Do I always need to buy the most expensive item, or is it enough to buy the cheapest as long as it is kosher?

Hello Rabbi,

It is ruled in Halacha (B.K. 9:) that one should invest up to a third in enhancing a mitzvah, but there is a dispute about what a third means, see the source. According to Halacha, the Shulchan Aruch rules as the main opinion that if one has an object for a mitzvah in a limited size, for example, an etrog in an exact size, there is an enhancement of the mitzvah to replace it with a larger object, for example, a larger etrog, and the amount to invest is up to a third of the price, for example, a small but kosher etrog costs 100 shekels, one should invest up to 133 shekels in the enhanced etrog. [That is, add 33 shekels, which is a third of the original price] And there are those who are stringent to invest up to 150 shekels [then from the final price a third 50 shekels is for enhancement, and two-thirds 100 shekels is the price of the mitzvah itself].

However, the Shulchan Aruch brought another opinion that it is advisable to be stringent that it is not necessarily about the size of the object, but any enhancement, for example, if the second etrog is more beautiful, it is advisable to invest another third in the price. [In this case, both forms of calculating a third are as above].

In the Gemara (B.K. 9:) it is stated that one should invest a third in enhancing a mitzvah, and there are 3 approaches to defining a third: 1. In the Jerusalem Talmud (Peah 1:1) it is stated that one should pay an additional third of the price to buy a more enhanced item. This is also the position of Rabbeinu Chananel (B.K. 9: d.h. אמר) and Rashi (B.K. 9: d.h. בהידור). 2. The position of Tosafot (B.K. 9: d.h. עד) is that one should increase the size of the object used for the mitzvah by a third of its original size. 3. The position of Rabbeinu Tam (Sefer Mitzvot Gadol, Positive Commandment 44) is that although the obligation to invest in enhancing a mitzvah is to buy a larger object, the third refers to both payment and size. According to Halacha, it is ruled (Shulchan Aruch, Orach Chaim, Siman 656, סעיף 1) as the position of Rabbeinu Tam, but it is also mentioned as the opinion of the Jerusalem Talmud, Rabbeinu Chananel, and Rashi. And as everywhere, where there is a main opinion and there is an opinion, the main opinion is taken as the main one, but there is room to be stringent according to the opinion. Regarding the method of calculating a third, there is a doubt in the Gemara (B.K. 9:) whether it is from the final price or from the initial price. Rabbeinu Chananel and the Rosh disagreed on how to rule according to Halacha. In practice, the Shulchan Aruch (Orach Chaim, Siman 656, סעיף 1) ruled leniently, but the Mishnah Berurah (סק"ג) brought the opinion of those who are stringent.