Actually if you have more expenses than income which is commmon in the first couple years the amounts are carried forward to be subtracted in a future year but doing with the CCA also works too.
I was also told it has to do with how long the item will be used in the sense that the CCA recognized that you make a large purchase up front like a fridge and then use it for 10 years so in a sense you claim part of the large cost each year of use.
I also use size of item as a factor too such as a swingset or playhouse whereas I would write off %200 of sand if I bought it in the year I bought it regardless since it is replaced more often.
Think of each item itself such as a $50 highchair vice a $200 bill for 4 chairs. So go by the individual cost of the item.
The regulations are sketchy since they don't take our type of purchases into account. I would argue a highchair or playpen is fully deductable in the year of purchase because it is needed right then and there and no guarantee that in 2 years you will have a child using it so it was an immediate requirement not a long term thing - even though you reuse it in the future if that makes sense.