Projecting global datasets for local analysis

I have some global datasets (eg SRTM, Landscan) which are geographic, they have data at say 30 arcsecond intervals.

I understand that if I want to do some spatial analysis on these data it's best to project them into a projected coordinate system. That's useful for a small country, or a small-ish study extent.

But what if I'm interested in projecting the geographic data on a large scale, perhaps the entire country or Russia? Do I split my study area into zones and use separate projects for those zones (like UTM), or is there a family of projections that's suitable for large scale analysis? Splitting them up into zones isn't great as we want to package them up for clients on a country-by-country basis.

I understand that choosing a projection depends on how much distortion you're willing to tolerate, and I'm sure selecting the size of your study area entails a similar decision. But what are the limits to PCS? Country? Continent? What are the accepted maximum extents for projecting global raster datasets?

Thanks