Vintage DateJust question

[DaveJV]

Hi All. I have been looking at purchasing a vintage TT DateJust 160133 made in the mid to late 80s. My questions are:

1) Will the old plexiglass crystal be a problem as far water leaking into case. I heard as the old plexiglass crystals age, they can distort/shrink some and the seal can ultimately leak water in the case ?

2) How much flex/bend in bracelet is too much before it has to be replaced?

3) Not known if its been serviced ever.

4) If I am not particularly into vintage watches, is it worth buying just because it is 60% less expensive than a new comparable DateJust.

See photos below

Thank you!