1501 questions

[uncufunc]

Hello all,

Inherited a 1501 from my late father a few years ago. I had the watch serviced in 2014 by Stuart Jefferson (Watchmasters) after receiving some recommendations here, but now have a few questions:

1) I rarely wear the watch, but when I do, I notice the seconds hand is not very smooth. After a day or so, it noticeably jumps on its way around the dial. I am used to the smooth glide of the 116710. Is a service in order or is this just how a vintage watch works?

2) The watch has an acrylic crystal, which explains my hesitance in wearing it as a daily. Anybody have experience fitting a vintage piece with sapphire?

Thanks in advance