Sorry for the random question but, is it necessary to keep count of the number of salawat, tasbeehat etc. that one does, or can one just repeat continously for a length of time and randomly swithcing to another? Do the numbers (100, 1000 etc) have any particular benefit? Sometimes I find it difficult to keep count and just repeat the salawat silently e.g. whilst working - is that kind of dhikr still beneficial?