7 Property operating expenses
| | 2019 | 2018 |
Taxes | 8,361 | 7,405 |
Insurance | 479 | 467 |
Maintenance | 29,096 | 25,724 |
Valuation fees | 630 | 598 |
Property management fees | 4,088 | 3,901 |
Promotion and marketing | 383 | 714 |
Letting and lease renewal fees | 6,209 | 5,284 |
Other operating expenses | 11,617 | 9,173 |
Addition to provision for bad debts | 419 | 273 |
Total property operating expenses | 61,282 | 53,539 |
In 2019, € 0.2 million (2018: € 0.6 million) of the maintenance expenses related to unlet properties.