aspirin questions

[scarlettsmum]

I was wondering if when you take aspirin daily as a preventative if you can develop some sort of resistance for when you need it therapeutically? Also in terms of dosing, all I can get here is 500 mg/pill of the uncoated variety and since I want to take this long term and am lazy to chop it up into minuscule pieces, would half = 250 mg per day be ok or is it too much when taken along with vitamin K2? I must have read all the threads on aspirin on this forum and RP quotes and am still not sure whether to go lower like 80 mg involving some extra work just to be on the safe side? Btw. I am pretty much healthy of normal weight and am used to aspirin, which always had only positive effects on me.