Quoted from Robotworkshop:
Maybe others will chime in too but it is certainly something to consider. They don't have to be huge, just something reasonable.
For the pad size, I've finally found the 'golden standard' which works very well for me. IPC-2222 Class A. This is the industry standard for most robust productability in low density applications.
To quote the IPC standard....
Hole size = maximum lead diameter + 0.25mm
Pad diameter = minimum hole size + 0.7mm (there's a longer formula, but this is what it works out to).
Before I found the formulas it was a lot of guesswork that didn't always go well. Just make sure to measure the max lead size properly for square pins, it's from corner to corner, not from flat to flat. I've done that a few times and it gives you holes that are too small.