Id like to understand "pipe size"
Modern split sytems we use generally have only one recommended size liquid/suction pipes, typically 3/8 5/8. and have eiter fixed capillary, or electronic exp valve. They have a maximum recommended pipe run.

When we come up against replacing am old system because the pipe runs hidden through the building, what is the effect of installing onto one or two size up liquid, or one or two size up suction line.

If we are going to instal a new system and the pipe length is significantly longer (50% and often not much height difference) than the manufacurers recommended, is it am advantage to increase the size of the liquid line.

In practice we have done this over the years and find that the systems give no trouble, however the manufacurers claim the compressor could either be starved of refridgerent or flooded, and destroyed. Id like to understand the theory and real life aspects.