I have in my workshop all the top brands of precision instruments, ranging thru Mitutoyo to Moore & Wright, all obtained during the time I was working for a living, and they have all stood the test of time very well.
But they are now consigned to the bottom draw after I purchased a set of Imperial and Metric Chinese micrometers and the same in dial verniers.
I couldn't believe the price they were at, but on checking them over and in comparison with the very expensive ones I have, I could find no difference in their overall measuring capabilities.
After using them for the last three years, almost continuously, and at times slightly abused, they have more than paid for themselves, and still read as accurate as the day I purchesed them.
What I am saying is that unless they have been used as adjustable C spanners, and really abused, by checking them out against the setting gauges, which should be with them, that should put your mind at rest as to their useability, and they should give you many years service.
If you are tight for cash at this time, they should be perfectly satisfactory for your use, and later, when funds allow, you can invest in the superior makes, and then do as I have done, put them away in the bottom drawer, in favour of the cheapo ones, which do a damned fine job.