WHY exactly do you want to buy these even while thinking they are too expensive? The only excuse for paying too much for an investment is if you think the rest of the market will continue to overprice it (greater fool theory of investing). It is only 'financially wise' when you pay what you think it is worth.
The way I make my decisions re RRbond.
* First decide I want to buy a bond because I feel bonds are the right investment for me.
* Second decide I think gov't bonds will earn me more (but within my risk tolerance) than corporates.
* Then I compare the returns of RRbonds vs normal long bonds (at bottom of this page
) to my personal expectation of inflation over the term of the bond.
* Almost always the inflation assumption within the yield of the RRbond will be higher than the inflation MOST people expect (because only people afraid of inflation buy these bonds). So you must make the trade-off: the lower yield vs the reduction of risk. That is a personal decision.
* Then I consider the alternate investment of a short-term bond which would also have little inflation risk. This again is personal.