TN for second term with current employer if want option to join startup later?

How does US currently view applying for new TN Visa a 3rd time, but within a six year period from original TN entry? Specifically:
1) First TN Visa at big tech company - years 1 - 3
2) Second TN Visa (renewal) at same big tech company - years 4 - 6
3) Third TN Visa at startup (< 7 people) - year #4 (i.e. while second TN Visa is still active)

Based on what I've read, my understanding is that the first renewal is usually ok (#2 above) and third time might give problems. Is that based on the number of TN attempts (1, 2, 3, ...) or the total years a person is on a TN Visa? (1-3, 4-6, 6+). Because if someone jumps at year #4 soon after getting TN Visa #2, that would be TN Visa #3, but still < 6 years. Thanks.


Registered Users (C)
There is no limit to the number of TN's you can have at one time, nor to the number of renewals. There is no 6 year limit. These stories are anecdotal at best, and apocryphal at worst.
Thanks Nelsona. You are of course absolutely right regulations wise as there is no specified limit. That said, practically speaking, don't the on-the-ground border agents usually say "no" at some point citing "intention" re: permanancy? What I heard was this is usually at the 7+ year mark when folks start noticing issues. Based on what you've seen, that's not the case?


Registered Users (C)
Mny here have been on TN for 15+ years. In fact, more time on TN indicates LESS of an inclination to immigrate, since one would have done so already.

CBP officers can complain all they want, but the truth is, they cannot deny a properly-documented, otherwise eligible applicant, based on "too long" or "too many".