By the way if you want to see the effect of whatever stat on dps, you can use
https://jklein.me/eqcalc/ or one of the ready-made spreadsheets. Going from 230->255 str is about 4 dps, which is just as much as going from 15->16 damage on your main hand (just non-backstab damage, obviously 16 main hand damage on a rogue would be bonkers).
The effect at lower levels is more pronounced--that is to say, I believe 25 str will net you about 2-4 dps using most calculators at any point, but that value obviously matters more when you're doing 20 dps versus when you're pulling 80. Note that str also increases your chance to hit as well as your max backstab damage, which these calculators can't really effectively estimate since a lot of to-hit chance depends on the type of mob you're hitting. It's a pretty stable, continuous benefit throughout your dpsing life. Best to get it out of the way asap when playing dps, though on a leveling monk I could see not maxing it instantly with minor twinking gear since you want to stay under the weight limit, which is quite restrictive at lower levels. On a rogue you should be at 255 str at all times though.