To the best of my knowledge I am answering your questions. Ok
1. Do we have to increase every profile parameter value which is displayed in red alert in transaction ST02 ?
Ans: Ofcourse it shoud be, since each buffer holds different values, wherever the red alert is there change the parameter value.
2. Why do the swapped objects always increase after a few days of tuning (in RZ10) & system restart?
Ans: Since more data had been fed into the server, it needs more space to hold in buffer while retrieving the data. Since buffer is shot in space, swap memory will be used. It is not enough to increase the buffer and that does not mean tuning, tuning in the sense full analysis of the problem and working in that particular area to resolve the issue. For example, creation of index, data archival, availability of statistics, alotting of no. of work process, etc.
3. Is there any standard in tuning ST02 to hold up the increasing value of swapped objects?
Ans: No. It depends on requirement.
4. After analysing ST02, how can we calculate the value of the parameter profile to be increased (in RZ10) ?
Ans: yes, use the command:
sappfpar check pf=\\usr\sap\trans\tpparam
(or)
sappfpar check pf=\\usr\sap\trans\tp_domain_<sid>
