In Keilim 16:1, the mishnah asks when wooden utensils are susceptible to tumah. The anonymous mishnah describes a bed or cot, and that it becomes susceptible after sanding; however, if the owner decided not to sand it, it becomes susceptible without the sanding. See the following extract:
כְּלֵי עֵץ, מֵאֵימָתַי מְקַבְּלִין טֻמְאָה. הַמִּטָּה וְהָעֲרִיסָה, מִשֶּׁיְּשׁוּפֵם בְּעוֹר הַדָּג. גָּמַר שֶׁלֹּא לָשׁוּף, טְמֵאָה.
When do wooden vessels begin to be susceptible to impurity? A bed and a cot, after they are sanded with fishskin. If the owner determined not to sand them over they are susceptible to impurity.
Much of the rest of chapter 16 further discusses this question for other utensils, but doesn't add the statement where the owner decides not to "finish" the utensil as usually would be done.
Does the same idea apply in all the cases, so that when an owner decides not to put the usual finishing touches on their utensil, it becomes susceptible (regardless of when the mishnah says it's "finished")? If not, why are beds and cots different?
I would guess that it applies in general, but we see repetition of laws in many cases in Keilim where we would expect a single case to suffice. Thus, I'm wary about making unwarranted generalisations here.