Well life is not calculated on years its on hours.
F404 had 3000-4000 hrs back then in 2010s.
Now some say f404 variant we using has a life of 6000-7000hrs..and overhaul time of 4000hrs. Gtre has not opened up what is life of kaveri. Nobody knows
The life of engine largely depends on how capable SINGLE CRYSTAL BLADES we have made....gtre has done alot of work on it it seems that kaveri will not have engine life less than a rd33. As r33 does not use SCB still it has life of 4000hrs (some might say It's 2200hrs because it's of rd93 variant of rd33 ,reduced life to compensate thrust for jf17)..
Both rd33 & kaveri are quite similar engines in terms of thrust rd33. But as it does t have strong SCB it has to use 4 LP stages & 9 HP stages..
Russian equipment is cheaper to buy but very expensive in long term. Simply there spares do t last that much compared to western counterparts the overhaul time of engines is very low compared to western counterparts..
Our babus will not let this happen.
Testing it on mig29 is not going to be easy it will not fit on that. Engines are modular to fit on any aircraft. Both have different dimensions kaveri is smaller in diameter & length it will require alot of changes in mig 29. If it is done it's worth rather than testing on single engine aircraft as even if kaveri fails we won't loose the aircraft