> ## Documentation Index > Fetch the complete documentation index at: https://docs.assetinfinity.ai/llms.txt > Use this file to discover all available pages before exploring further. # Depreciation > What the fleet is worth, in every accounting book that has an opinion about it, and the monthly run that charges it. Depreciation tracks what the fleet is worth over time, in one or more accounting **books** at once — distinct from [budgets](/finance/budgets), which tracks approved spend rather than asset value. ## One asset, several books A tenant can keep more than one book — most commonly one that goes into the statutory accounts and a separate tax book that computes a deduction — and an enrolled asset is depreciated under all of them at once. The two are expected to disagree: a machine can be fifteen-year straight line in one book and sit inside a 15% written-down-value block in another, in the same month, and neither figure is more correct than the other. Depreciation doesn't pick a winner between them — an asset's own [Finance tab](#on-an-asset) shows every book's carrying amount side by side. This is a licensed module and only appears where your organisation has it. Where it's on, some jurisdictions ship a **country pack** that sets both books up in one step — see [Configuring depreciation](/config/depreciation). ### Pooled books A book can be **pooled**: it depreciates a whole block of similarly-rated assets as one written-down value rather than machine by machine. Additions go in, disposal proceeds come out, and no individual asset inside a pooled book has a carrying amount of its own. This is how a tax regime with block-of-assets rules works, and the **Blocks** tab only appears once a pooled book exists. ## The monthly run The main screen opens on **This month**: which books have an open period with nothing posted for it yet, so a gap doesn't stay invisible until the year's closed and somebody goes looking for it. Running a book computes a draft; posting hands it to the ledger as a journal, which fails by named class if no posting rule is mapped for it — worth finding out before the month end rather than at it. Every enrolment is either charged or excepted in a run, and the exceptions are read before the total: | Reason | Meaning | | - | - | | Nothing capitalised into this book yet | No cost basis | | No policy rule covers its class | | | Not in service until after this period | | | Already written down to its residual | | | Suspended by hand | | | Its policy has no life or rate to work from | | | It has left | Disposed | | No meter of the kind this book depreciates it by | Units-of-production only | | Its meter reads lower than it did, with no rollover to explain it | | | It did no measured work this period | | ## The register A tab of carrying amounts per asset per book — the figure people ask for most, once the monthly act itself is out of the way. ## Assets and capital projects **Assets in the register and in no book** is counted explicitly, because enrolment is deliberate: being on the asset register doesn't put a machine into a book on its own. A **Projects** tab (where capital projects are in use) shows capital spend accumulating against a project before it's capitalised onto the register as an asset — see [Organisation structure](/config/organisation-structure) for what a project is. ## Disposals, history and journals Disposing an asset ends its depreciation in every book it's enrolled in and records the result. **History** is every run, posted or not; **Journals** is what was actually handed to the ledger. ## On an asset An asset's own **Finance** tab (gated on the module, so it doesn't appear where depreciation isn't licensed) shows its carrying amount in every book side by side, the dated cost events its basis is built from, and lets you capitalise, revalue or revise an enrolment directly against the asset rather than through the register. Country packs, books, classes, policies, rules and the accounts a book posts to.