One hundred 1-hour tasks or one 100-hour task
Are these the same really? I know that mathematically they are, but do they represent an equivalent effort for your product?
Most of the time they don’t.
On one hand, having multiple low-complexity tasks is good to keep a large team busy. You will usually find ways to parallelize the work by having different people work on different tasks at the same time. There’s no reason you can’t do this with only one big task, but the former is usually simpler.
Smaller estimates will also tend to be more accurate than bigger estimates, where there’s a lot of hidden complexity that we can’t understand until we get close enough to the work.
On the flip side, one hundred tasks are just too many opportunities to make a mistake, to harbor scope creep, to have too many balls in the air at the same time. More moving things represent more complexity.
Make sure you consider everything at play before you let math play tricks with your estimates.