Being asked to use reasonable endeavours sounds less onerous than best endeavours; is that correct?
That is correct. An obligation to use best endeavours has been defined as a duty to leave no stone unturned and to take all reasonable courses of action. It is not an absolute obligation to ensure that something happens and it probably depends on the particular circumstances. Thus an obligation in SBC clause 188.8.131.52 that the contractor will constantly use best endeavours to prevent delay does not amount to a guarantee that there will be no delay. If that was the case, there would be no need for an extension of time clause. In contrast, it has been held that an obligation to use reasonable endeavours only requires a party to take one reasonable course of action even though there may be several different courses available. It follows that if a party is asked to use ‘all reasonable endeavours’ it is the same as being asked to use best endeavours because both require that all the available reasonable courses of action are taken.