Hospitality is an honour in Tajik culture. Tips are not expected but gift can be given if you stay with a village of family.
Practically all restaurants, cafes, teahouses automatically add on a 5-10 % service-charge to a bill, but it is a common practice to leave the change, or to add something as a personal gratuity.
At the hotels it is customary to tip the junior staff and cleaners, who are often underpaid.
Tipping a tour guide is a matter of personal choice, but certainly tips are always welcomed.
Tip attendants in religious and historical monuments for which no entrance fee is charged.
For toilet attendants, if any, 0,50-1 Somoni is enough.