This is appropriate – there is no maximum amount of time between treatments – your success in removing your tattoo does not depend on sticking strictly with a schedule of visits. This is different that with other medical advice – particularly in the area of taking medication – your body may need to keep a consistent or minimum level of an antibiotic to maintain effectiveness.
With tattoo removal it is different – during your laser procedure ink is shattered in tiny pieces, and the amount of time you wait does not affect the amount of ink that has been broken up. Waiting a minimum of 3 weeks will allow your body to flush away the majority of the ink. For most patients 4 weeks is more than enough. Waiting longer will not hurt – but it also will not help.