How often do you increase weights/ how much you lift now?

For those who workout regularly, how often do you increase your weights? Or better said, after how much time you feel like you need heavier ones?

I have been working out on a regular basis for about 2 months and the heaviest weights I had were 4kg (8,8 lbs). And they seem so heavy for me, when I first bought them last year (yeah, I worked out inconsistently, or mostly focusing on hiit/ cardio and never managed to put in more strenght workouts).

Right now I am on week 2 of FB Burn and I already starting to find my 4kg weights, not so heavy anymore. I still get burned with them, but slower, aka I need more reps to start feeling the burn.

Today I went to buy 5kg ones (11 lbs), so I can push myself even more. I finally understood that lifting heavy is helping me get lean, not bulky, so I am looking forward to buy a heavier set, maybe next month?

So, how about you? How often you change them and also, how much do you lift now? When I see Kelli lifting 30/40lbs ones I realise how far behind I am :)). Probably this is one of the reasons I decided to push myself more and start increasing the weight.