Question lang... How do you know if shocks are busted?

Here's the thing. I don't feel na matagtag naman yung ride, and wala naman akong naririnig na unusual na creaks, kalampag or any weird sounds. One thing I did notice a while ago though was parang di masyado grippy yung front tires ko, mas madaling mag skid ang gulong when hard braking. Although I thought this was because nagpalit ako ng front tires, and baka hindi lang sya ganun kakapit. Ngayong napansin kong iba yung tindig ng oto ko, baka related 'to dun.

I did the push-down test, well, merong 1 very slight bounce pag bitaw, although it's been like that since I got the car. Di ko pa nasilip though kung merong leaks.

I ask because parang naging dropped yung oto e. Usually stock na bigbody GLi, mga 5 finger gap. Sa'kin before is a 4 finger gap and ganun na sya since I got the car a little over a year ago, and never got it checked why mababa sya. I just checked a few minutes ago, and it's just barely a 3 finger gap.

Actually ang ganda nga ng drop kaya lang baka naman bigay na bigay na yung shocks ko.

Ano kaya 'to? Any better test I can do to check? Anything else I should look out for?

Thanks in advance sa mga sasagot.