Because I am in Canada, I track very little, mostly using Letter rates, even for US and overseas shipping.
Tracking through Canada Post starts at $12 and that is only for domestic /regional. Domestic/national is higher.
On low value items (based on my purchase costs) I don't bother.
On bulky items I have to use Parcel rates, so those are tracked.
I agree with @caldreamer that if you are faced with a Not Received Claim on an untracked shipment, you might as well just refund because you cannot win.
But OTOH, you saved a lot of money* shipping without tracking dozens of other items.
I also agree that at $3.99 or even $5.99 you may be clearing space, but you are not making any money. In addition to your actual costs, you should be paying yourself at least minimum wage, which here is 25c a minute.
Where I disagree is on Seller Rating. Although I don't use tracking often, I hold Top Rated Seller status, albeit as a Global seller, which does have some differences. For example, my badge only shows on my pages outside of the USA.
But I still get the other perks, like a lower FVF.
Side note, you can't buy LetterRate labels online, but you can buy discounted mint postage on eBay. Avoid the Forever booklet offers, most of those appear to be counterfeits, but many stamp dealers do have genuine stamps from philatelic estates in huge quantities which make your packages look more interesting. Some chain stores also sell genuine stamps at reasonable discounts.
*That $12 tracking on a 50gr item going within my own province would cost me $1.30 to ship without tracking.
