help from diamond+ player please

i run into this problem a fair amount, its not every game but

pink wards: scenario: i have enough gold for a completed last slot item, im a support player. do i buy the zzrot/dmp/sv or do i keep 2 pinks on me?

wards on the map: 3 sightstone wards top lanes 2 wards mids blue adc's blue jungle usually has a sweeper, maybe he will have a tracker if lee sin or something.

obviously thats not 100% every game. squishies without ward hops usually get blue trinket top lanes full of tank/bruisers can get close to a bush so they normally get a yellow.

i mean in theory i feel like 7 wards placed property is definitely enough, but its solo queueu and we're not on com and lets be real. most people waste their wards in weird locations