I am a firm believer in dollar cost averaging and just had a question about it. Dollar cost averaging requires the person to invest equal monetary amounts regularly and periodically over specific time periods. However, in theory, shouldn't a person's salary steadily increase throughout their career (assuming it is a successful one, of course)? If they steadily invest more of their money in their investment fund (e.g. they always invest 12% of their income), they are technically not dollar cost averaging because they are not investing 'equal monetary amounts'. Does anyone know what DCA theory says about this, i.e. the how to dollar cost average with a steadily increasing income?