Just changed 2 pair tyre. When do the alignment the tyreman said meed to adjust chamber bcoz 'lari' about 30° as shown below. Do i need to adjust chamber?

I saw that the tires wear out on the outside.
But I just rotated the tires few months back.
Not sure if it wear before or after I rotated.

Yep, worn or new absorber /absorber mounting could alter the camber/toe-in numbers . But the numbers may still be within OEM range specs and out of spec as well , IDK .

Not sure by 'adding' camber on 1 side means shifting camber angle towards positive or negative , can anyone help elaborate or explain ?

However , adjusting camber angle of one side only I suspect there was a difference in camber between the sides . Having said this, before adjustment both different camber angles could still be within range , we don't know without like the computer screen shot by akatsukea above  .

Hi, from the day after adjusting camber on one side to the day you recently change the tyre set you found alignment is not out .

May I know whether you do regular tyre rotation in between ? If so 10,000 km or ?

How many years or km during this interval ? 3 years ?

Toe-in can be adjusted without extra cost in parts .

Since you paid extra and it has something to do with "nut"  ,in the absence of wheel alignment screen shot here , I would speculate that computer camber reading is out of specifications which implies adjustment of camber angle is required .

However camber adjustment is not possible in your car design (what car model is this ?). Hence extra cost in camber nut parts replacement .

In other words, this tyre centre workshop has not conned you but did the job right , IMHO .

Me too is no fan of wheel alignment , neither do I practise tyre rotation .

From your experience here , total absence of periodic alignment and tyre rotation is all right for up to 3 years .

Thanks for the elaboration/clarifications .