Ugly screens and a long click path do not mean you must rip it out. Rebuild costs migration, training, a parallel window — and may zero codes still in use. Extend costs adding features in a tangle of wire, getting more brittle each time. Weigh: is the master data still worth keeping, does the floor still walk these documents, and can anyone change the code or the config.
A full packaged ERP that only opened the GL, while inventory still lives on sheets, is closer to “no system.” Reskinning it does not help. See A packaged ERP nobody uses is almost as bad as having none. Packaged vs. custom is whether the software can follow your exceptions. See How packaged software actually differs from a custom system. When SaaS misses the floor, more config rarely rewrites the state machine. See When SaaS does not match how the floor actually works.
Rebuild does not mean wiping history
If you rebuild, you still move codes and open documents. See How to move old data and spreadsheets into a new system. Keep finance software if you can; rebuild the operations layer, then talk interface. See Do you have to connect finance and the ERP you already run. Phase one covers the main path only so the new system does not become another fat empty shell. Cost lives in migration and the parallel window, not pretty pages. See What a custom business system costs and how long it takes.
If you extend, first freeze what you will not do: do not force a production scheduler onto the old architecture, do not fill every report at once. Each add is accepted when the floor walks one fewer old road. When DaXi Technology assesses an old system we look at source or vendor support, where real documents land, and whether master data can still be master. Send live screenshots to the Business systems service page. The full path is in From brief to launch: how we build a business system. When the floor has fully bypassed the old system, extend hours often cost more than rebuild — every cut has to dodge old logic that may explode.
A black-box system needs a read-only survey before a quote
Some old systems become a black box after the key person left: no docs, table comments in pinyin. “It still opens” is not “it can change.” Do a read-only survey first: table shape, key stored procedures, whether there are add-ons. Quote after that, so you do not sign a “small change” and deliver an archaeology dig. During rebuild, do not shut the old system until cutover day. In the parallel window both sides write; match differences daily. Do not drop the old books when the new system “feels good.”
There is also a fake extend: a new skin and a phone shell, while the state machine is still a ten-year departmental pile. The floor still bypasses it. An extend must bind one old-road close — for example “after this change, outbound must scan a system document.” An extend with no close condition is the same as no change. A rebuild must list numbers you inherit: customer codes, item codes, open contract numbers — especially those printed on cartons and in the customer’s system. Weigh both pans, then sign. That is cheaper than starting and later arguing “why is this getting slower.” A license still in term is not a reason to renew: if operations already moved out, renew finance and stop the manufacturing suite.