I don't take much notice of service history. I think you can tell by the "smell" of a car if it's any good or not... so use The Force!
Basically 90% of cars must get serviced properly at around the correct service intervals for the frst three years... since the first owner either spent their own moolah on the beast (and so will look after it) or it's a company car...
Then around 5 years the car ends up in the independent dealer networks which is either a good thing or not, depending on the garage used (so what's their stamp actually worth?)
Then if it survives to 8 years, it's looked after by the "crazy fool" who bought an old, 100k Alfa..

and he does all the jobs himself... :thumbs:
It's more handy if you have MOTs and receipts for something.. since that helps to diagnose problems (like how long has that clutch been in there) and you can gauge the owner's attitude to fixing it (genuine parts, or the cheapest aftermarket stuff he could find?)
You can also check the mileage.. and its pattern. Regular 10,000 miles per year suggests no problems with the car.. up and down mileage may be a bit more worrying.
Ralf S.