You 'saved' the lesser of:the difference in cost of the 'trashed' planter from buying one in good condition, minus your parts and time; or the cost of hiring someone else to do the rebuild. 

Saying you saved the price of a new planter by refurbishing a 20 year old one quite a ways from honest.  You still have a 20 year old planter.  It is worth more then it was 'trashed' but it is not worth anywhere near the cost of a new one, or even a recent model one in similar condition.

Overvaluing assets is a good way to work oneself into a financial bind.   

I'm a firm believer in letting someone else take the depreciation on new equipment.  We farm with a line of equipment which is predominately well used and which is regularly rebuilt.  But,  I do not delude myself into thinking that I have new equipment when I have rebuild old equipment.