No, why would you?

I've had the same budget file running since 2016, and while my pay and wider expenses have changed wildly over that time, the core of my budget (every day expenses) hasn't ballooned because I'm able to use historical averages as goals.

Also, longer term expenses - new phone, new mattress, etc - I am already saving for, a fresh start would wipe all that out.

The only benefit I can see to a fresh start would be if I stopped using ynab for a prolonged period of time and I didn't want to do a massive historical import.

I do a fresh start every year. I like cleaning out the payee's, closed accounts, and making broad stroaks of changes.

Fresh start is a way to make it easy to get back into using ynab. If you've been consistently using it up until now, I don't see a reason to bother with it.

No. I like having the historical data and being able to see trends in my net worth and spending over years. YNAB lets you hide closed accounts and unused categories, so I don't feel like my budget is cluttered with stuff I don't care about.

In the past, I used a fresh start when I was first starting out with YNAB. My first few budgets were experiments and served the purpose of letting me figure out how the software worked. When I finally got a good handle on how it worked, I did a fresh start and set up everything the way I liked it.