Do bobstays need turnbuckles?

[JohnV]

I'm planning a standing rigging replacement. The boat is a 33' Alajuela, a heavy cruiser. The bow platform is on a tubular aluminum frame and extends 29".
The bobstay is 3/8" 1x19 with the original (I think) 35 yr-old Navtec 500 turnbuckle. Can't say its length offhand but obviously not so long that I'd expect stretch to be much of a factor. The jibstay and backstay are adjustable.
Seems to me that a bobstay turnbuckle is redundant. The different forces acting on the bowsprit must vary a lot. I'd think that would make minute changes in the geometry of the triangle of which the bobstay is one leg. So, if true, the bobstay length must change minutely regardless of the original turnbuckle tension.
There seems to be some variety of opinion on this, and I'd appreciate feedback from this forum.
Thanks in advance.
John V.